--What do you think of cloning?--No doubt it’s a great invention. But ________, it may have some side effects.
It was a real race _______ time to get the project done. Luckily, we made it.
(2013·山东,28)________ I have to give a speech, I get extremely nervous before I start.
I had hardly got to the office ______ my wife phoned me to go back home at once.
I have heard a lot of good things about you ________ I came back from abroad.
There's no way of knowing why one man makes an important discovery ________ another man, also intelligent, fails.