Sometimes they discuss to each other.()

A.to

B.at

C.with

D.against

hem for food. Sometimes, however, two kinds of animals come together in a partnership (伙伴关系 ) which does good to both of them. You may have noticed some birds sitting on the backs of sheep. This is not because they want a ride, but because they find easy food in the parasites (寄生虫 ) on sheep. The sheep allow the birds to do so because they remove the cause of discomfort. So although they can manage without each other, they do better together.

Sometimes an animal has a plant partner. The relationship develops until the two partners cannot manage without each other. This is so in the corals (珊瑚 ) of the sea. In their skins they have tiny plants act as "dustman", taking some of the waste products form. the corals and giving in return oxygen which the animal needs to breathe. If the plants are killed, or are ever prevented from lighting so that they cannot live normally, the corals will die.

1、Some birds like to sit on a sheep because ().

A、they can eat its parasites

B、 they depend on the sheep for existence

C、 they enjoy traveling with the sheep

D、 they find the position most comfortable

2、The underlined word "they" in the last sentence of the first paragraph refers to ().

A、birds and parasites

B、birds and sheep

C、parasites and sheep

D、sheep, birds and parasites

3、What does the second paragraph mainly discuss？ ()

A、Some animals and plants depend on each other for existence.

B、 Some animals and plants develop their relationship easily.

C、 Some plants depend on each other for foo

D、 Some animals live better together.

4、What does this article talk about？ ()

A、Two kinds of animals for a partnership.

B、Most animals only have connection with animals.

C、The connection between the living things.

D、Corals have some connection with plants.

A.gulf

B.distance

C.gap

D.issue

hands with each other.()

此题为判断题(对，错)。

ts to _76 teenagers to study in groups 77 the evening. I know we get 78 sometimes, but we 79 a lot from each other. We also think that vacations should be 80 . At present they’re too short. Longer vacations would give us time to do things 81 volunteering. Last summer I had an 82 to volunteer at the local hospital, but I couldn’t because I had to _84 back to school. It would be a good _84 for me because I want to be a doctor when I’m 85