在沙漠、干旱草原烈日当空的旷野产生的蜃景属于全反射。( )

什么叫可采储量？

(三) Researchers have shown that noise can adversely affect human in both physiological and psychological ways. Hearing losses in particular occupations such as ship - building and con- structi - on work are well - known. In fact, however, we all find hearing more difficult as we age. Young ears can distinguish a wide range of sounds from low to very high frequencies, while older ears lose the ability to distinguish high -pitched sounds. A comparison of people living in some industrialized and non - industrialized areas suggests that this hearing loss may not necessarily accompany old age. Furthermore, a closer inspection of other data reveals economic effects. For instance, an increased turnover in property has been observed in noisy areas near airports. Job performance can be adversely affected by loud noise, especially if accuracy and mental effort are involved. The use of outdoor areas for conversation is not possible for an estimated 5 to 10 million people who live or work in urban areas. When interference with television or speech or sleep is included, as many as 22 to 24 million people can be said to have lost part of the use of their homes and grounds because of noise. Thus noise pollution is a serious environmental concern. The indifferent attitude toward noise should be overcome; considerable efforts should be made to alert people to the grave effects that may stem from an excessively noisy environment.

The last paragraph implies that______

A．people are generally concerned about noise pollution

B．many people haven’t yet realized the adverse effects of noise pollution

C．people are making efforts to overcome the noise problem

D．people are alert to excessively noisy environment

保荐人应当自持续督导工作结束后（）个工作日内向中国证监会、证券交易所报送《保荐总结报告书》。

A．5

B．10

C．15

D．20

简述斜拉桥和悬索桥的受力特点。

投用液面计的操作步骤？