The old man died ____ cold ____ a cold night.
  A. from； at   B. of； in　 C. of； on   D. for； during

Scientists are convinced ____ the positive effect of laughter ____ physical and mental health.

A. of; at　 B. by; in　 C. of; on　　 D. on; at

He is blind _____ his mistake in the composition.

A. in 　 B. of　 C. to 　 D. about

-----You’re so lucky.

-----What do you mean_______that?

A. for　 B. in　 C. of　 D. by

Scientists are convinced ____ the positive effect of laughter ____ physical and mental health.

A.of; a B. by; in 　 C. of; on D. on; at