问题
选择题
Yesterday it rained heavily when school was over. So we _______ tay in our classroom.
A. should B. must C. had to
答案
答案：C
题目分析:昨天放学时雨下的很大，所以我们只好呆在我们的教室里。A. should应该； B. must 必须；C. had to不得不，根据句意及时间状语yesterday（昨天）此题选B。