Experiments of this kind _______ in both the U.S. and Europe well before the Second World War.(2011北京卷21)
The headmaster has promised us that we shall be told ________ the results of the exam come out.
You can't go out since you haven't finished your homework; ________, it is a stormy night.
The victims suffering from the terrible earthquake have to be provided accommodations if they ________.
I have read the material several times but it doesn’t make any ______ to me.
The reporter is _______ a dilemma whether he should report the footballer who is guilty ______ taking a bribe.