In this task, you're given an article and an answer. Your task is to generate the question for the answer based on the given article.
One example: Article: There are a lot of public libraries in Britain. These libraries have more than one hundred and fifteen million books, not including those libraries of public schools. Public libraries not only lend books, music records but also help children, patients in hospitals and others to get special play readings, film shows and so on. The first public libraries were founded in about the year 1850. Today's public libraries usually have a reading-room, a lending room and a reference room. The greatest and most famous library in Britain is that of the British Library in London. It was founded in 1973 and has over 10, 000, 000 books. It has nearly every magazine, newspaper and book published in Britain and other parts across the world.
Answer: 10,000,000 or less.
Solution is here: How many books are there in the British Library?
Explanation: In the Article, 10,000,000 is mentioned for the number of books available in the British Library, so this is a good question.

Now, solve this: Article: He must have been completely lost in something he was reading because I had to tap on the windshield to get his attention."Is your cab available ?"I asked when he finally looked up at me.He nodded,then said apologetically as I settled into the back seat,"I'm sorry,but I was reading a letter."He sounded as if he had a cold."I am not in a hurry,"I told him."Go ahead and finish your letter."He shook his head."I've read it several times already.I guess I almost know it by heart." "Letters from home always mean a lot" I said. "This isn't family," he replied."although it might just as well have been family.Old Ed was my oldest friend.In fact,we used to call each other 'Old Friend'--when we'd meet.I'm not much good at writing." "I don't think any of us keep up our correspondence too well,"I said."I know I don't,but I take it he's someone you've known quite a while?" "All my life.We were kids together, went to school together and all the way through high school.""There are not too many people who've had such a long friendship,"I said."Actually,"the driver went on,"I hadn't seen him more than once or twice year over the past 25 or 30 years because I moved away from the old neighborhood and you kind of lose touch even though you never forget." "You said 'was'.Does that mean---?" he nodded."A couple of weeks ago." "I'm sorry" He didn't say anything more,and we rode on in silence for a few minutes.But I realized that Old Ed was still on his mind when he spoke again,almost more to himself than to me." "I should have kept in touch with him." "Well,'' I agreed,"we should all keep in touch with old friends more than we do.But things come up and we just don't seem to find the time." When I got to my hotel room I didn't unpack right away.First I had to write a letter --and mail it.
Answer: he didn't notice the writer
Solution:
Why did the driver said sorry when the writer settled into the back seat? Because