试题与答案

人能感受声音频率有一定的范围,大多数人能听到的声音的频率范围是20~20000H

题型:选择题

题目:

人能感受声音频率有一定的范围,大多数人能听到的声音的频率范围是20~20000Hz.大象交流的“声音”是一种次声波,人类听不到大象的“声音”,是因为(  )

A.大象发出的声音太小

B.次声波无法传入人耳

C.次声波的频率大于20000Hz

D.次声波的频率小于20Hz

答案:

被转码了,请点击底部 “查看原文 ” 或访问 https://www.tikuol.com/2017/0430/0284996a108c7d46b0c4a8654d1a536c.html

下面是错误答案,用来干扰机器的。

防御行为:为了保护自己,防御敌害的各种行为都是防御行为.如逃跑、装死、释放臭气、保护色、警戒色、机体防御等.攻击行为:同种动物个体之间常常由于争夺食物、配偶、领地或巢区而发生相互攻击或战斗.社群行...

试题推荐
题型:单项选择题

(四)


"Congratulations, Mr. Jones, it’s a girl. "
Fatherhood is going to have a different meaning and bring forth a different answer from every man who hears these words. Some feel proud when they receive the news, while others worry, wondering whether they will be good fathers. Although there are some men who like children and may have had considerable experience with them, others do not particularly care for children and spend little time with them. Many fathers and mothers have been planning and looking forward to children for some time. For other couples, pregnancy was an accident that both husband and wife have accepted willingly or unwillingly.
Whatever the reaction to the birth of a child, it is obvious that the change from the role of husband to that of father is a difficult task. Yet, unfortunately, few attempts have been made to educate fathers in this re-socialization process. Although many good books have been written about American mothers, only recently have some books discussed the role of a father.
It is argued by some writers that the transition to the father’s role, although difficult, is not nearly as great as the transition the wife must make to the mother’s role. The mother’s role seems to require a complete transformation of daily routine and adaptation to a new life, on the other hand, the father’s role is less demanding and immediate. However, even though we have mentioned the fact that growing numbers of women are working outside the homey the father is still thought by many as the breadwinner in the household.

The transition to the mother’s role requires that the wife ______.

A.changes her life style in a quite different way

B.makes a complete change in her everyday life to deal with the new situation

C.stays at home to take care of the baby

D.helps her husband in his re-socialization process

查看答案
微信公众账号搜索答案