Question

Choose the correct word or phrase that completes the sentence correctly.

This problem is a hard nut ____.

• A. for cracking
• B. to crack
• C. in cracking
• D. with cracking

Answer 1

The correct option is B to crack

Option B is the only correct answer to this question because 'a hard nut to crack' is a very commonly used idiom that refers to a problem that is very difficult to solve or a person who is very difficult to understand.

Options A, C and D are incorrect because they do not complete the idiom correctly and are grammatically incorrect as well.