1 . Justin wanted to buy some hand-made silver accessories as souvenirs. He was told that the price will depend on the ______ of silver.

A．percentage

B．principle

C．gravity

D．option

2 . Mars has less g________ because its density (密度) is smaller than the earth. Someone who weighs 50 kilos on the earth weighs only 19 kilos on Mars! (根据首字母单词拼写)

8 . 根据句子意思，选择方框内合适的单词并用其适当形式完成句子。

hatch                      hike               grasp                 hang                    guarantee highlight                      guard             hesitate            harvest             greet habitat                  genuine            herb               guard               gymnastics handkerchief          heaven            guideline          headline            gravity

1. We cannot ________ that our flights will never be delayed.
2. He ________ my hand and shook it warmly.
3. The house ________ by two large dogs five years ago.
4. You can ________ some curtains over the windows to protect your private life from prying eyes.
5. He often goes ________. Hence he is healthy.
6. We're at your service. Don’t ________ to turn to us if you have any further problems.
7. The report exposed how she and her lover ________ a plot to cheat her husband.
8. Your resume should ________ your skills and achievements.
9. The farmer hired extra workers ________ the fruit before the first frost.
10. When he saw me he ________ with a friendly “hello”.
11. When starting a new business, try to follow these general ________.
12. There are two ________ on duty at the gate.
13. Many ________ are used in traditional Chinese medicine.
14. He uses a ________ when he sneezes or coughs.
15. This is a ________ Ming vase, not a fake. Be cautious. It is fragile.
16. Don’t make a noise. I’m listening to the news ________ .
17. The ball falls to the ground because of the force of the ________.
18. With so many areas of woodland being cut down, a lot of wildlife is losing its natural ________ and many species are in danger of extinction.
19. Sang Lan is a famous gymnast. She began learning ________ when she was only six years old.
20. He believed that he and his wife would one day be together again in ________.