______ to sunlight for too much time will do harm to one’s skin.
Don't mention that at the beginning of the story, or it may _____ the shocking ending.
Gun control is a subject_______ Americans have argued for a long time.
He played the computer games till late last night,____ early this morning.
Mr. Wang made up his mind to devote all he could______ his oral English before going abroad .
They _____ building the new hotel because of the great cost.