It is still unknown_______ caused the accident last Saturday.
| A．that | B．when | C．what | D．how |
The number of people invited _____ fifty, but a number of them ______ absent for different
reasons.
| A．were; was | B．was; was | C．was; were | D．were; were |
He ______ have attended the meeting t
his morning. He has been staying at my home for a whole day.
| A．can’t | B．mustn’t | C．shouldn’t | D．needn’t |
______ another button and your meal is prepared and heated for you.
| A．If you press | B．To press | C．Press | D．Pressing |
Many teens don’t get enough sleep because they have ____ homework, ____makes them stay up at night.
| A．much too; which | B．too much; that | C．much too; what | D．too much; which |
I failed in the examination last term and only then ____the importance of study.
| A．I realized | B．I had realized | C．had I realized | D．did I realize |