1. Effectove measures should be taken tokeep the environment from being polluted.
2. The novelist had written 6 detective novels by the end of this year.
3. I was very glad to see him last night as we hadn't see each other for quite a long time.
4. You should pay attention to what you say and do, which will affect your life.
5. The project has to be put off due to the lack of money.
6. The key to grasping a foreign language is to communicate with others in it.