搜题请搜索小程序“爱下问搜题”
问题 选择题

下列属变态发育的动物是：

A．蚯吲

B．蜘蛛

C．青蛙

D．蛇

答案

答案：C

该题考查的是动物的发育方式，变态发育一般指昆虫纲与两栖动物的发育方式，两栖类的变态发育要经过四个时期，如青蛙：受精卵--蝌蚪--幼蛙--成蛙，其中幼体和成体的根本区别是呼吸方式，幼体用鳃呼吸，成体用肺呼吸，皮肤也能辅助呼吸，昆虫纲的变态发育和两栖类有所不同，因为它们的变态发育又分为完全变态与不完全变态。

单项选择题

All her life, my mother wanted busy children. It was very important that her house should remain at all times clean and tidy.
You could turn your back for a moment in my mother’s house, leave a half written letter on the dining table, a magazine open on the chair, and turn around to find that my mother had "put it back where it belonged," as she explained. My wife, on one of her first visits to my mother’s house, placed a packet of biscuits on an end table and went to the kitchen to fetch a drink. When she returned, she found the packet had been removed. Confused, she set down her drink and went back to the kitchen for more biscuits, only to return to find that her drink had disappeared. Up to then she had guessed that everyone in my family held onto their drinks so as not to make water rings on the end tables. Now she knows better.
These disappearances had a confusing effect on our family. We were all inclined to forgetfulness, and it was common for one of us, upon returning from the bathroom, to find the every sign of his work in progress had disappeared suddenly. "Do you remember what I was doing" was a question frequently asked, but rarely answered.
Now my sister has developed a secondhand love of clean windows, and my brother does the cleaning in his house, perhaps to avoid having to be the one to lift his feet. I try not to think about it too much, but I have at this later time started to dust the furniture once a week.

This passage mainly tells us that

A．my mother often made us confused
B．my family members had a poor memory
C．my mother helped us to form a good habit
D．my wife was surprised when she visited my mother
查看答案
单项选择题

我们无法控制的误差是（）

A、疏忽误差

B、缓变误差

C、随即误差

D、系统误差
查看答案