Question

【题目】— Could you please come to the museum with me this afternoon?
— Sorry, I ________. I have to take a piano lesson at 2 pm.
A.couldn't
B.mustn't
C.can't
D.needn't

Answer 1

【答案】C
【解析】句意：—今天下午你能跟我一起来博物馆吗？—对不起，我不能，我下午2点要上钢琴课。could用于疑问句表示委婉的请求，其回答用can。couldn't表示过去不能；mustn't表示禁止“必须不，一定不能”；can't不能；needn't表示不必。故选C。