Her brother be at home now because he was seen playing basketball in the stadium just now

问题补充：

Her brother be at home now, because he was seen playing basketball in the stadium just now.

A. mustn’t

B. needn’t

C. can’t

D. shouldn’t

答案：

A. mustn’t

B. needn’t

(答案→)C. can’t

D. shouldn’t

解析：考查情态动词。句意为他的哥哥现在不可能在家，因为他刚才在体育馆打篮球。can 表示推测时，主要用于否定句和疑问句中。所以选C。