-- _____is that used for?---_____ the floor.
Children’s brains cannot develop properly _________ they lack protein.
Afraid __________? This type of anxiety can deeply disturb people’s enjoyment of social relationships.
Experts and teachers all think that failure is not _____ a bad thing to some extent.
Although Albert Einstein would someday be _________ famous scientist, he did not like __________ school.
—Shall we go out for a meal tonight?—__________. We haven’t been out for ages.