—What do you think our descendants(后代) be like in thousands of years?—Who knows exactly what happen to human beings?
– What do you think of the book ? -- Oh, excellent. It’s worthy ______ a second time.
. It was some time _____ we realized the truth.
Having a trip abroad is certainly good for the old couple, but it remains _____ whether they will enjoy it.
—What does this sentence mean ? --- It seems to me that it ________.
Don’t leave matches or cigarettes on the table within ____ of little children.