environmental damage is done, it takes many years for the ecosystem（生态系统）to recover.
| A．Even if |
| B．If only |
| C．While |
| D．Once |
Our new house is very __________ for me as I can get to the office in 5 minutes.
| A．adaptable | B．comfortable | C．convenient | D．available |
The Olympic Games in the year 2012 ________ in London, which ______ known
to us all.
| A．is to hold; are | B．is to be held; was |
| C．are to hold; is | D．are to be held; is |
I seem _______ a bad cold.
| A．to catch | B．to have caught | C．catching | D．having caught |
Many people consider it _________, from which a lot of children benefit.
| A．a worth doing cause | B．a cause worth to do |
| C．a worthwhile cause | D．a worthless cause |
---It’s a long time _____ I saw you last.
---Yes, and what a pity it is now that it will be a long time _______ we see each other again.
| A．before; since | B．since; when | C．since; before | D．when; before |