He get into his own house because he has lost his keys.A. mustn’t B. doesn’t have to C.

问题补充：

He get into his own house because he has lost his keys.

A. mustn’t

B. doesn’t have to

C. can’t

D. needn’t

答案：

A. mustn’t

B. doesn’t have to

(答案→)C. can’t

D. needn’t

解析：情态动词辨析。A.禁止 B. 不必 C. 不能，不可能D. 不必。句意：他不可能进入他自己的房子，因为他已经丢了他的钥匙。结合语境可知选C。