Once fighting _________ between the two villages and many people were killed.

A. broke out    B. was broken out     C. had broken out     D. had been broken out

选词填空并用适当的形式：

accident, believe，rag, decade, develop, surface, explode, float, solid，account, force , spread

1. They thought it was ___________ for them to walk so far in one day.

2. Henry was looked down upon by the waiters, for he was in ________.

3. He has made a great plan of two _______ for his son when he was born, and then he will be 20 years old.

4. We wondered whether he did it on purpose or by ________.

5. With the ________ of our country’s economy, people's living standard has been greatly raised.

6. More than 70% of the earth’s _______ is covered by water.

7. During World War II, two atomic bombs _______ in Japan, killing a large number of people.

8. The ____________ of gravity makes things fall to the earth.

9. They __________ the canoe out into the middle of the river.

10. The bad weather _________ for the long delay of the plane.

The mammals             (繁殖) when the animals, harmful to them, disappeared.

 Zhang Heng was one of the most famous Chinese a             in the world.

There is a big underground railway             (系统) in London, which is good for travelers.

By the time they reached the top of the mountain, they were            (精疲力尽).

You will              (逐渐地) get used to the weather here.

One cannot e            without air.

The illness is s           through the village.