单项选择题21()
A.requireB.needC.wantD.lack
填空题Noise constitutes a real and present danger to ______ .
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Noise is America’ s most widespread ______ .
填空题What does runoff mean