Question

Fill in the blank with the most appropriate word.
This problem is hard _____ because it is very complicated.

• A. solving
• B. to solve
• C. solved
• D. be solved

Answer 1

Answer: (B)

to solve

The infinitive verb is a verb with the word 'to' in front of it. This verb is always just a verb. There is no - ed, no - ing, no - s at the end of the verb. to-infinitive is used with adjective. Thus, options A, C and D are wrong according to the rule. The correct option is B since 'to' is in front of the verb 'solve' and adjective 'hard' is used in the sentence.