介词 at 表时间 — 英语词汇题
题目
补全句子：在钟点前填入正确的介词，使句子通顺（每空一词）。1. Mike usually has breakfast ____ seven o'clock. 2. My sister goes to bed ____ nine o'clock. 3. Helen does her homework ____ five o'clock in the afternoon. 4. They watch TV ____ six o'clock in the evening.