[填空题]People have different nutritional needs at different life stages.

[单项选择]
People like different kinds of vacations. Some go outside. Others like to stay at a hotel in an exciting city. They go shopping all day and go dancing all night. Or maybe they go sightseeing to places such as Disneyland, the Tai Mahan or the Louver.
Some people are bored with sightseeing trips. They don’t want to be "tourists". They want to have an adventure, to learn something and maybe help people too. How can they do this Some travel companies and environmental groups are planning special adventures. Sometimes these trips are difficult and full of hardships, but they’re a lot of fun. One organization, Earth Watch, sends small groups of volunteers to different parts of the world. Some volunteers spend two weeks and study the environment. Others work with animals. Others learn about people of the past.
Would you like an adventure in the Far North A team of volunteers is leaving from Mormons, Russia
A. a shopping center
B. a hotel
C. a dancing hall
D. a place of interest

[填空题]People can have meals there.

[单项选择]How many people worldwide have been infected with HIV since the start of the epidemic
A. 47 million.
B. 4 billion.
C. 25 million.
D. 44 million.

[单项选择] Thigh, robot People who have suffered debilitating strokes often have to cope with impaired muscles that do not work properly. Even a simple act such as standing up from a chair and walking a few steps can become extremely difficult. Stroke victims often have to rely on wheelchairs, sticks, walking frames and other "orthotic" devices to move about. But a new generation of active orthotic devices, capable of augmenting or replacing lost muscle function, is in the works. These devices use an assortment of complex computer and mechanical technology, borrowed from the field of robotics, to help patients get around. They are being made possible by the falling prices and improving performance of sensors, computer control systems and battery technology. As well as benefiting elderly patients with permanent paralysis or muscle dysfunction, such devices could also help people in recovering from "arthroscopic" (literally, "looking within the joi
A. True
B. False
C. NOT GIVEN