He failed the mid-term examination and only then________how much time he had wasted.
| A．he realized | B．did he realize |
| C．he had realized | D．had he realized |
environmental damage is done, it takes many years for the ecosystem to recover.
| A．Even if |
| B．If only |
| C．While |
| D．Once |
---Could you do me a favour?
----It depends on it is.
| A．which |
| B．whichever |
| C．what |
| D．whatever |
There have been several new events to the programme for the Olympic Games.
| A．add |
| B．to add |
| C．adding |
| D．added |
tomorrow, our ship will set sail for Macao.
| A．However the weather is like |
| B．However is the weather like |
| C．Whatever is the weather like |
| D．Whatever the weather is like |
----She looks very happy. She have passed the exam．
-----I guess so. It’s not difficult after all.
| A．should |
| B．could |
| C．must |
| D．might |