Question

【题目】You always be careful with electricity for safety.

A. mustB. canC. mustn'tD. can't

Answer 1

【答案】A

【解析】

句意：为了安全，你必须经常小心用电。

考查情态动词辨析。must必须，强调主观意愿；can能，表能力或许可，否定式是can't；mustn't不能，表禁止。根据be careful with electricity for safety可知BCD三项不合句意，故选A。