It was _____ it raised so many difficult questions _____ the book took a long time to come out.
| A．that; that | B．since; which | C．because; that | D．because; which |
China is one of the countries ________ the Mekong River flows.
| A．in which | B．by which |
| C．across which | D．through which |
He was _________by his colleagues though he himself didn’t think he had done anything special.
| A．thought little of | B．thought poorly |
| C．thought highly of | D．thought highly |
It was reported that a chemical factory________ last night, which killed thirty workers.
| A．exploded | B．cracked |
| C．ruined | D．burst |
The exhibition is well worth ________ and you can see fancy vases of different dynasties on show there.
| A．to visit | B．to be visited |
| C．being visited | D．visiting |
Only when he reached the tea-house _________ it was the same place he’d been in last year.
| A．he realized | B．he did realize |
| C．realized he | D．did he realize |