初二下期英语试题阅读理解问题Mr.Smith usually got up late in the morning,so

初二下期英语试题阅读理解问题
Mr.Smith usually got up late in the morning,so Mrs.Smith always called him up in order to make him not to be late for work.One day,they had a loud and long quarelling,so they were not speaking to each other.In the evening Mr.Smith handed his wife a piece of paper.He had written" call me at 7 in the morning" on it.Then without a word,he went to sleep.
Next morning,when Mr.Smith woke up,it was already 9:30.He got up and put on his clothes quickly.As he went out,he found another piece of paper on the table." It's seven o'clock.Get up!"
( )4.Mrs.Smith woke up the next morning_______.
a.before 7 b.after 7 c.at 9:30 d.at 6:30
( )5.Mr.Smith woke up late by _______.
a.two and a half hours b.one hour c.half an hour d.about three hours
D,我不解,
也许,可能,答案本身就不对,至少我这样认为。热切期盼其它网友的意见看法，
第4题D答案 at 6:30，在短文中未发现有明确信息表示为 6点30分，如果此答案是对的，那么说，at 6:31,6:32...7:00都对啦？如果这些都有可能，那就是A.before