题目内容：

A

Water had also appeared on other planets like Mars but, 1. the earth, it 2. later. It was not immediately obvious that water was to be 3. to the development of life. 4. many scientists believe is that the continued presence of water allowed the earth to dissolve 5. gases and acids into the oceans and seas.

B

Some people have the idea that you can cross Canada in less than five days, but they forget 6. Canada is 5,500 kilometres from coast to coast. Here in Vancouver, you’re in Canada’s warmest part. People say it is Canada’s most beautiful city, 7. by mountains and the Pacific Ocean. Skiing in the Rocky mountains and sailing in the harbor make Vancouver one of Canada’s most popular cities 8. in. Its population is increasing rapidly. The coast north of Vancouver has some of the oldest and most beautiful forests in the world. It is so wet there that the trees are 9. tall, some 10. over 90 metres.