搜题请搜索小程序“爱下问搜题”
问题 选择题
已知f(x)=
x+3，x≤-1
x2，-1＜x＜2
3x，x≥2
，若f（x）=3，则x的值是（　　）
A．0B．0或
3
2
C．±
3
D．
3
答案

若x≤-1，由f（x）=3得x+3=3，解得x=0，此时不成立．

若-1＜x＜2，由f（x）=3得x2=3，解得x=

3
，此时成立．

若x≥2，由f（x）=3得3x=3，解得x=1，此时不成立．

综上：x=

3
，

故选：D．

听力题

根据单词首字母或汉语提示，用所学单词的正确形式填空。

小题1:China has got a good r_______ for fighting against the flu with its careful and smooth organization.

小题2:As there is less and less coal and oil, scientists are exploring new ways of making use of a________ energy, such as sunlight, wind and water for power and fuel.

小题3:We arrived at our d_______after traveling across a large mountain.

小题4:He thought he was likely to become a l_______ figure in the company where he worked.

小题5:There is a fine little cafe o_______ the cinema. Cross the street and you’ll be there.

小题6:With the windows _______(测量)，my mother went to buy cloth to make curtains.

小题7:Unfortunately, he got _______(困住) in the traffic before the interview.

小题8:The accident was caused by a wrong _______(判断) on the part of the pilot.

小题9:_______(农业) is still largely based on traditional methods in some countries.

小题10: He was _______(禁止) to leave his room as a punishment.
查看答案
填空题

腭帆张肌的运动受（）支配。
查看答案