16. ----It’s getting dark, but Mr. Johnson is still at his office.
----No surprise. Who else can _____ he does?

10. ----What’s that noise?
----Oh, I forgot to tell you. The new machine _____.

50. You won’t be able to see him because he ______ a meeting in Suzhou when you arrive.

41. If it ______ for the fence, he ______ into the river.
A. were not; fallen                                    B. had not been; could have fallen
C were not; could fall                                    D. had not been; could fall

40. I could have offered you some help last weekend, but I ______ with my work at that time.

37. I would rather you ______ in my school, Mom.

35. It was the fifth time that he ______ to such a meeting.

27. I wonder whether the police ______ that lost child or not

11. The public has complained that large quantities of waste water ______ into rivers without being cleaned, so large amounts of money ______ to solve the problem.

6. Measures have been taken to prevent accidents, but much ______ for more improvement.