单项选择题
Africa is the second largest continent in the world, Yet much of Africa has not been developed by man into farms and cities. One of the reasons is that a dangerous and unpleasant insect called the tsetse fly(采采蝇)is found there. This fly makes its home in the heart of Africa.
The tsetse fly is a little larger than the housefly. Its name means "fly that destroys cattle". It lives by sucking blood from animals. It attacks man, as well as his herds of cattle.
The tsetse fly carries sleeping sickness to those men it bites. Sleeping sickness makes men veryill, and some forms of it cause death. The tsetse fly also causes diseases in animals. In some places in Africa, it has destroyed whole cattle herds.
It is hard for man and his cattle to live with the tsetse fly. Some experts even think that it has kept 400 million square miles of Africa a wilderness. This wilderness is a place as large as the whole United States. Without the tsetse fly, more land could be used by man.
Without it, many more cattle could be raised. People are working to get rid of the fly. However, it is a hard job and will take a long time.
A. People do not like the sound it makes.
B. It eats food that people need.
C. It has killed many cattle herds.
D. It can destroy the crop there.