Shortly after the traffic accident, two _______police were sent to the spot to keep order.
| A．dozen of | B．dozens | C．dozens of | D．dozen |
29. The nutrients in ____ falls into the ocean will quickly become available to other living creatures.
| A．whichever | B．that | C．whatever | D．Wherever |
28. I don’t think you’ve quite__the seriousness of the situation. You seem to know nothing about it.
| A．recognized | B．mastered | C．grasped | D．Seized |
20．The river, ________ banks are covered with trees, is beautiful and it attracts many water birds.
| A．whose | B．what | C．of which | D．which of |
19．From this year’s poor results, one can see ______ many changes have been made in the football team and that, sadly, it is no longer ______ it once was.
| A．that; what | B．what; that | C．what; when | D．that; where |
18．______ everyone knows, John has made his promise to his parents ______ he will never play computer games again.
| A．As; which | B．As; that | C．It; that | D．It; which |