.Most birds find it safe to sleep in the trees, but __________ they have eggs or young chicks, they don’t use a nest.
| A．why | B．how |
| C．unless | D．where |
The officials soon realized that, __________, things would get worse.
| A．unless dealt with it properly | B．if not properly dealing with it |
| C．unless properly dealt with | D．if dealt not properly with |
Fully _____ in looking after three children at home, she no longer has time to enjoy various activities in the club.
| A．attached | B．occupied | C．contributed | D．devoted |
The next day, the group of villagers had not gone very far ____ they entered a very narrow passage between two mountains.
| A．after | B．when | C．until | D．while |
—I can’t find Mr. Smith. Where did you meet him this morning?
—It was in the hotel ___ he stayed.
| A．that | B．where |
| C．which | D．the one |
—Are you free after school?
—Sorry, I’ve planned to treat a friend of mine to dinner ______ for help.
| A．in order | B．in return | C．in turn | D．in honor |