问题描述：
we _____a worse day for the picnic----it rained all day.
A couldn't pick B can't have picked C shouldn't have picked D mighn't pick
答案为什么选B?我觉得C也可以啊
A couldn't pick B can't have picked C shouldn't have picked D mighn't pick
答案为什么选B?我觉得C也可以啊
问题解答：
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