Don’t be so discouraged. If you ______ such feelings, you will do better next time.

To discuss “population as a global __________ ”, we are supposed to know about the history of population trends.

I’m sorry I broke the window.–I’m afraid you have to______ it.

How do you think he managed to improve hisEnglish in such a short time—______ four hours on it every day．

The weather in London is so changeable that people always take their umbrellas with them________rain.[ ]