1. ________ returning from abroad, he set about setting up a club for young climbers.
A. Upon B. At C. In D. During
2. The River Nile ________ flood large areas, but now the waters of it ________ electricity.
A. is used to, used to produce B. used to, are used to producing
C. used to, used to produce D. used to, are used to produce
3. In the end she decided to sell the house ________ windows face south.
A. which B. that C. what D. whose
