1. Natural resources are ..... decreasing.
a. rapid b. rapidity c. rapidty d. rapidly
2. You can send your letter ...... surface mail.
a. by b. in c. to d. with
3. We have apartment ........ the park.
a. overlooking b. overlooks c. to overlook d. overlooked
4. I really must answer all the letters which are very important ( reduce relative )