He usually goes to school ____ bike, but sometimes he _____a taxi to school.
The floor is so wet. Let’s _______.
The flood in 1998 washed lots of houses _______ and lots of people _______.
—I’d like to take five days off, Mr. Smith. —______ . Don’t you know we’re very busy these days?
—We only live once, but if we live a wonderful life, once is enough. — ________ I agree.
As we all know, great changes _______ in China in the past thirty years.