单项选择(每题1分)—Look, John’s fallen asleep at work!—Oh, he must have _____ late last night.
It is generally believed that teaching is _____ it is a science.
She made a note of it ______ she might forget.
He succeeded in solving all the problems _____.
It was ________ done _______ Marry jumped up with joy.
The teacher will give us an interesting talk _______ you said.