A、Toys for children. B、Important documents. C、Food and coffee. D、Clothes and scientific papers. D细节题。短文结尾提到，the speaker登机后打开手提箱后

I had to go to Amsterdam last week for a conference. I arrived at the airport in plenty of time and checked in. But I only had one small case, so I decided to take it on the plane as hand luggage.[19]As the flight was not due to board for 45 minutes, I went to a cafe, sat down and ordered a cup of coffee. While I was sitting there, drinking my coffee and reading the paper, I was vaguely aware of a woman and her child coming to sit at the next table. I did not pay much attention to them though. And when my flight was called, I reached for my case and left.
    An hour later, the plane was in the air and I decided to look at the conference programme to see what I wanted to attend.[20][21]Imagine my horror when I opened the case and found that it was full of picture books and children’s toys. And imagine what the woman must have thought about a case full of men’s clothes and scientific papers.
19. Why did the speaker go to a cafe?
20. What was in the speaker’s case?
21. What did the speaker find out on board the plane?