单项选择题
| Questions 17-20 are based on the following passage. You now have 20 seconds to read questions 17-20. |
What does the speaker suggest people should do when they go shopping
单项选择题 21（）
单项选择题 22（）
单项选择题 How many solar heat panels do three or four bedroom homes usually need
单项选择题 What is the purpose of building new houses facing north or south
单项选择题 What’s the problem with paper napkins and plastic food wraps
单项选择题 Which is not true about solar heat collector panels
填空题 What is the passage mainly about
单项选择题 Why is insulation required in new houses
单项选择题 What’ s the talk mainly about
填空题 What characteristics can be of a flood
单项选择题 What do we learn about the use of solar energy in the USA
单项选择题 What is the main topic of the lecture
填空题 What does "runoff" mean
填空题 How much of all precipitation is runoff
填空题 Noise can produce serious ______ stress.
填空题 Noise constitutes a real and present danger to ______ .
填空题 Noise is America’ s most widespread ______ .