题目

完形填空 John is a famous writer now. But he said he was not a __1__ student when he was young. He was often late for __2__ and didn't like doing his homework. Sometimes, he slept in class while the teacher was teaching. He didn't understand much, __3__ he always thought he understood everything. One day the teacher __4__ the students a question, When Jack was ten years old, __5__ brother Bob was twenty. Jack is fifteen now and  __6__ is his brother Bob? John said, That's easy. Bob is twice as old as Jack, so he is now thirty.  Another time, the __7__ in a science class asked, W用竖式计算 46＋38=(   )