A、Walking the dog. B、Cutting the grass. C、Watching the children. D、Feeding the fish. C细节题，选项都是家务事。A、D两项属于take care of his pets的范

M: I really don’t know what to do this summer. I can’t afford to just sit around, and there don’t seem to be any jobs available.
W: Why don’t you try house-sitting? Last summer my friend Margaret house-sat for the Dodds when they went away on vacation. Mr. Dodd hired Margaret to stay in their house because he didn’t want it left empty.
M: You mean the Dodds paid Margaret just to live in their house?
W: It wasn’t that easy. She had to mow and water the houseplants. And when Eric house-sat for Mr. Cohen, he had to take care of his pets.
M: House-sitting sounds like a good job. I guess it’s a little like baby-sitting—except you’re taking care of a house instead of children.
W: The student employment office still has a few jobs posted.
M: Do I just have to fill out an application?
W: Margaret and Eric had to interview with the houseowners and provide three references each.
M: That seems like a lot of trouble for a summer job.
W: The houseowners want some guarantee that they can trust the house-sitters. You know, they want to make sure you’re not the type who will throw wild parties in their house, or move a group of friends in with you.
M: House-sitters who do that sort of thing probably aren’t paid then.
W: Usually they are paid anyway just because the homeowners don’t want to make a fuss. But if the homeowner reported it, then the house-sitter wouldn’t get another job. So, why don’t you apply?
19. What does the man want to do this summer?
20. What did the Dodds do when they went away last summer?
21. What is one responsibility the house-sitter probably won’t have?