1 . Billions of poor people around the world     1     (depend) on the use of wood for cooking. And as they take more and more firewood from wild areas, they are destroying habitats around the world. Wood collection is one reason why many animals have become endangered.

This is     2     Dr. Metcalf spends each summer in Africa. He wants to teach women and children in villages how to cook with the sun. He helped create Solar Cookers International. It’s an organization that introduces solar cookers to developing countries     3     teaches people how to use them.

2 . ––The small restaurant is always crowded in every part.
––That’s ______ it has a unique dining environment and quite a few wonderful dishes.

A．why	B．because
C．where	D．when

3 . 40 grams of meat per day is ______ people should consume in order to stay fit.

A．that	B．why
C．how	D．what

4 . The famous player tried again and again after each failure. That’s _____ he succeeded at last.

A．what	B．when
C．whether	D．why

5 . What I love most about reading novels is ______ the authors vividly describe the characters.

A．what	B．why
C．how	D．whom

6 . —I heard you wanted to have a further study in a foreign college.
—Yes, that's _____I try my best to learn English well.

A．when	B．how
C．what	D．why

7 . An accident happened on the main road. That is ______ traffic seemed to slow suddenly.

A．why	B．how
C．when	D．what

8 . The most exciting moment was ____ I was given the first prize.

A．which	B．where
C．why	D．when

9 . They have leading experts in this field, and that’s ____ they’ve made important progress.

A．where

B．why

C．whether

D．who

10 . －How do you usually find out about new software?
－In the magazines like Popular Electronics. That’s______computer companies usually advertise.

A．which

B．where

C．what

D．why