—Is Jim in the office?—No,he________to the dining hall.
Not only oral English but also written English _____ important.
—We’ll make a trip to Hainan Island next weekend. Will you go with us?—No, I can’t _____ it at present.
—How many students are there in the classroom?—_____ I don’t know where they have gone.
The rubbish _____ is produced every day is becoming a serious problem in cities around the world.
More and more trees were cut down. _____, many animals are dying out.