--- Would you like to _____ Professor Smith’s lecture this Sunday?--- Sorry, I have an important meeting to _______.

—  Why don’t you go into the office ,John —I have ______ my office keys at home.

Wastes from the factory ______the water pollution in this area. 

I’m beginning to regret that I ______ the job, for I’m working overtime every evening．

We had a marvelous holiday: only the last two days were slightly _____ by the weather.