It seems oil____from this pipe for some time, we’ll have to take the machine apart to put it right.
| A．had leaked | B．is leaking |
| C．leaked | D．has been leaking |
___ more and more people may refer to the Internet for the latest news, it is unlikely that the newspaper will disappear．
| A．When | B．Because | C．Since | D．While |
—I'm sorry; I shouldn't have been so rude to you．
—You ___ something not very nice to me, but that's OK．
| A．have said | B．had said | C．were saying | D．did say |
—Can you describe ___ it happened?
—Yes, I was riding on my bike ___ a car knocked me down from behind．
| A．when; as | B．how; as | C．how; when | D．how; while |
The train CRH380A, ___ trial operation on the Shanghai-Hangzhou high-speed railway, set a speed record of 416．6 kilometers per hour．
| A．started | B．to start | C．starting | D．being started |
We went to the West Lake yesterday, ___, not surprisingly, was crowded with visitors from all over the world．
| A．where | B．which | C．that | D．when |