Correct answer: A. into
Explanation:
The correct preposition here is “into”. We use “into” to describe movement or action directed toward the inside of a place or container.

• “Into” is used when something is being moved or placed inside something else. For example, “Throw this pen into the dustbin” means that the pen is being moved inside the dustbin.
• “In” is used when something is already inside a place (e.g., “The pen is in the dustbin”).
• “On” is used when something is placed on top of a surface (e.g., “Place the book on the table”).
• “None” is incorrect because the sentence requires a preposition to indicate direction or movement.
Examples:
• He jumped into the pool.
• She poured the milk into the glass.
• Don’t put your shoes on the bed.

Thus, “Throw this pen into the dustbin” is grammatically correct because “into” conveys the movement of the pen into the dustbin.

Correct answer is D. at.
We use the preposition “at” to describe a specific location or position relative to a larger place or object. The phrase “at the back of” is a standard prepositional phrase used to indicate that something is located in the rear part of something else.
Other options:
• A. about: This means “on the subject of” or “approximately.” It does not describe a physical location (e.g., “We talked about the house”).
• B. in: We use “in” for things that are contained within the space. While you can say “in the kitchen,” you wouldn’t typically say the kitchen is “in the back” of the house in this context. “In the back” is often used for areas within a larger, open space (e.g., “She sat in the back of the theater”).
• C. of: This preposition shows possession or relationship, not physical location (e.g., “the color of the kitchen”).
Therefore, “The kitchen is at the back of the house” correctly specifies its location at the rear of the building.

Correct answer: B. from
Explanation:
The correct preposition here is “from”. We use “from” to indicate the source or origin from which something is freed or removed.
“From” is used to express liberation or removal from something, especially in the context of danger, harm, or a difficult situation. For example, “The children were freed from the danger” means that the children were rescued or relieved from being in danger.
The structure is: free + from + [danger/problem/suffering]
Examples:
• The medication freed her from pain.
• We all wish to be free from fear.
• The organization works to free animals from suffering.

Other Options:
• A. of: While “free of” is also correct, it is used to describe a state of being without something, often something undesirable that is already absent. “Free from” emphasizes the act of escaping or being removed from the danger.
o Example of “free of”: “This drink is free of artificial colors.” (It doesn’t contain them.)
o Example of “free from”: “The hostages were freed from captivity.” (They were released from it.)
In this context, the children were removed from a dangerous situation, making “from” the better choice.
• C. with: This indicates accompaniment or means (e.g., “freed with the help of the police”). It does not indicate separation from danger.
• D. in: This indicates location or state (e.g., “freed in the forest,” “freed in good condition”). It does not convey the meaning of being removed from a threat.

Correct answer: C. of
Explanation:
The correct preposition here is “of”. We use “of” to indicate the cause of death, illness, or a condition.
• “Of” is used to express the cause of something, especially when referring to death or illness. For example, “That child died of heavy fever” means the fever was the cause of the child’s death.
• “At” is used for specific points in time or location, not for causes.
• “For” indicates purpose or reason, but not the cause of death.
• “With” is used to indicate an accompaniment or presence of a condition but doesn’t correctly indicate the cause of death.
Thus, “That child died of heavy fever” is grammatically correct because “of” is used to indicate the cause of death.

Correct answer: A. off
Explanation:
The preposition “off” is used to indicate movement away from or separation from a surface. In this sentence, the bedclothes are being moved away from the bed.
The phrasal verb “pull off” means to remove something from a surface it is on.
Why the other options are incorrect:
• B. between: This is used for a position in the middle of two separate things (e.g., “The sheet was pulled between the bed and the wall”). It doesn’t describe removal from the bed itself.
• C. on: This indicates movement to a position on a surface (the opposite of the intended meaning). “Pulled on the bed” would mean they were placed onto it, not removed.
• D. across: This means from one side to the other (e.g., “The sheet was pulled across the bed”). It describes movement over the surface, but not removal from it.
Examples:
He pulled the blanket off the sleeping child.
Please take your feet off the table.
The cat knocked the vase off the shelf.
Therefore, “Every time I was about to sleep, my bedclothes would be pulled off the bed” correctly describes the action of the bedclothes being removed from the bed.

Correct answer: D. at
Explanation:
The verb “hint” is typically followed by the preposition “at”. The phrase “hint at” means to suggest or indicate something indirectly.
The structure is: hint + at + [something suggested]
Why the other options are incorrect:
• A. of: While “hint” can sometimes be followed by “of” in more poetic or older English, the standard modern preposition is “at.” “Hint of” is more commonly used as a noun phrase (e.g., “There was a hint of sarcasm in her voice”).
• B. for: This preposition indicates purpose or a recipient (e.g., “a hint for the puzzle,” “a hint for you”). It is not used after the verb “hint.”
• C. with: This means “by means of” or “accompanied by” (e.g., “She hinted with a wink”). It is not the standard preposition used to link the verb to the thing being suggested.
Examples:
The data hints at a significant economic shift.
His letter hinted at his upcoming retirement.
What are you hinting at?
Therefore, “He hinted at some loss of treasure” is the correct form, meaning he indirectly suggested that a treasure was lost.

Correct answer: C. for
“For” is used when talking about the cause or reason for something. For example, “the reason for his absence” refers to the cause or explanation behind his absence.
The noun “reason” is followed by the preposition “for”. This structure is used to explain why something happened or exists.
The pattern is: the reason for + [noun/noun phrase]
Examples:
The reason for the delay is bad weather.
She explained her reasons for resigning.
Is there a reason for this chaos?

The other options (“on,” “of,” “for”) do not fit grammatically in this context:
o “On” is used for specific times or places, but not for reasons.
o “Of” is used to show possession or characteristics but not reasons.
o “For” is the correct preposition, but it was not listed among the available options.

Correct answer: B. since
Explanation:
The preposition “since” is used with a specific point in time (e.g., Monday, 2020, last week) to indicate that an action started in the past and continues up to the present. It is used in sentences that are connected to the present, often with the present perfect tense (“has not read”).
The structure is: has/have + (not) + past participle + since + [specific point in time]
Examples:
I have lived here since 2015.
She hasn’t eaten since breakfast.
It has been raining since morning.
Why the other options are incorrect:
• A. for: The preposition “for” is used with a duration of time (e.g., for two days, for a year). “Monday” is a specific point in time, not a duration.
• C. from: “From” indicates a starting point but is typically paired with “to” or “until” to show a time range (e.g., “She worked from Monday to Friday”). It is not used with the present perfect tense to connect a past action to the present.
• D. over: “Over” can mean “during” (e.g., “over the weekend”) or “more than.” It does not correctly convey the meaning of an action starting at a specific point and continuing to now.
Therefore, “She has not read anything since Monday” correctly means that from Monday until now, she has not read anything.

Correct answer: D. with
Explanation:
The correct preposition here is “with”. We use “in conformity with” to indicate agreement or compliance with something, such as rules, standards, or laws.
Ex: Be careful with the thieves.
Grammar Rule:
• “In conformity with” is a fixed phrase used to express that something is in agreement or alignment with rules, guidelines, or standards. For example, “This is in conformity with the rules laid down by the Corporation” means that the action or situation complies with the Corporation’s rules.
• “For” is used to indicate purpose or intended recipient, but not for expressing compliance or agreement.
Ex: It is a movie for kids.
• “Against” expresses opposition or resistance, not conformity.
Ex: We were rowing against the tides.
• “About” generally refers to subject matter or topics, not conformity.
Ex: There’s something strange about this person.
Thus, “This is in conformity with the rules laid down by the Corporation” is grammatically correct because “with” is used to indicate compliance or agreement

Correct answer is B. by.
The preposition “by” is used to indicate the method or means used to achieve something. In this sentence, “adding the date of birth” is the method we use to “obtain the answer.”
The structure is: Achieve a Goal + by + Method/Means
Examples:
She learned English by watching movies.
You can unlock the door by turning the key.
We saved money by cooking at home.

Other options:
• A. to: This preposition often indicates direction or purpose (e.g., “the answer to the question,” “I went to the store”). It does not describe a method.
• C. on: This indicates topics, surfaces, or specific days (e.g., “a book on grammar,” “the paper is on the table”). It does not describe a method of doing something.
• D. in: This is used for periods of time, locations, or states (e.g., “in June,” “in the room,” “in trouble”). It does not explain how an action is performed.