若|x|=|-3|,则x=______.
∵|x|=|-3|=3,
∴x=±3,
故答案为:±3.
用达尔文的观点,长颈鹿长颈的形成是[ ]
A.代代伸长颈的结果
B.自身想伸长的意识所致
C.自然选择的结果
D.经常吃高处的树叶所致
The students have cleaned the classroom,_____?[ ]
A. so they
B. don’t they
C. have they
D. haven’t they