John is a famous writer now. But he said he was not a good student when he was young. He was often late for ___21___ and didn't like doing his homework. Sometimes, he slept in class while the teacher was teaching. He didn't understand much, but he always thought he understood everything. One day the teacher ___22___ the students a question, “When Jack was ten years old, ___23___ brother Bob was twenty, Jack is fifteen now and how old is his brother Bob?” John said, “That's easy. Bob is twice as old as Jack, so he is now thirty.” Another time, the ___24___ in a science class asked, “When it thunders (打雷), why do we always see the light before we ___25___ the sound?” “But, Miss,”said John quickly,“don't you know our eyes are in front of our ears?”
选项：

A:teacher
B:his
C:asked
D:class
E:hear