问题
选择题
--- Mum, could I play with my classmates for a while after I finish my homework?
--- _______. But you must come back before supper.
A．Yes, you can
B．Yes, you could
C．No, you can’t
D．No, you couldn’t
答案
答案：A
本题答语的含义是晚饭前你必须回家，根据答句的含义应该是对问句的肯定，could构成的的一般疑问句，回答是不在拥有委婉礼貌的语气，不在用could，而应该用can，故本题选A。