Question

Fill in the blank with the most appropriate word:
It’s wise to be careful _____ one’s health.
a. to
b. by
c. of
d. at

Answer 1

Hint:
 Choose the answer which correctly establishes the relation between “being careful” and “health”. One is usually careful about someone’s things.

Complete answer:
Prepositions are words that are placed before nouns or pronouns to create a relation between the word and the remaining part of the sentence.
(a) to- “To” is used when we are talking about an endpoint and it usually involves a transfer or movement. She went from Mumbai to Pune. She gave the gift to her brother (a transfer of gift from someone to another). It’s wise to be careful to one’s health. There is no implication of any movement or transfer.
(b) by- “By” is used when we show that work was done by someone. “It’s wise to be careful by one’s health” is not an appropriate usage since it does not show any action done by someone.
(c) of- “Of” is used to show the constituents of something. The dress is made of cotton. It is also used to show possession. She should take care of her things. Similarly, It’s wise to be careful of one’s health. This is the right answer.
(d) at- This is used to show a target. She threw the pen at him. It is also used to specify a time- Meet me at 8 AM.
The correct option is option C .

Note:
While using prepositions, see if the relation between the object and the subject has been established. If you are confused about any answer, frame your own sentence with the preposition. Prepositions can be learned from books or grammar websites.