阅读下列短文，从每题所给的A、B、C三个选项中选出最佳答案。

April 24^th is Space Day of China. Ever since Yang Liwei made it to space in 2003, about 20 Chinese astronauts have been sent into space.

In space, astronauts face many problems. There is little gravity（重力）there, which influences their bodies. Also, being away from family and friends and staying in a tiny spaceship for a long time can make them feel sad or stressed out. What’s more, if something goes wrong suddenly, they have to fix it under huge pressure. That’s why astronauts have to be smart, strong, and ready for any challenge before they can go to space.

To make sure that Chinese astronauts complete their tasks and return to Earth safely, 8 kinds, including over 200 subjects of training, are set. Besides physical training, basic science knowledge and mock（模拟）tasks are included. Before astronauts can go to space, they train like this for at least three and a half years.

In China’s manned space project, one of the most difficult parts of the training is the underwater training. This helps astronauts get ready for the weightless environment in space. And they wear diving suits（潜水服）over 100 kilos and stay underwater for six hours every time.

（1）What problem do astronauts face according to paragraph 2?

A．	They have to train under huge pressure.
B．	They are influenced by little gravity in space.
C．	They often worry about their family and friends.

（2）What do astronauts need to do before going to space?

A．	Master basic science knowledge.
B．	Experience 8 subjects of training.
C．	Get three years of underwater training.

（3）What does the underlined word “This” in paragraph 4 refer to（指代)?

A．

A diving suit.

B．

Underwater training.

C．

China’s manned space project.

（4）What can be the best title for this text?

A．

Work Hard to Live in Space

B．

Train Hard to Work in Space

C．

Deal with Problems in Space