已知一组数据1,2,0,-1,x,l的平均数是1,则这组数据的极差为( )
A.2
B.3
C.4
D.5
(1+2+0-1+x+1)÷6=1
∴x=3
∴极差=3-(-1)=4.
故选C.
Last year was a hard time to my friend Jim, but he didn’t_____ hope.
A.pick up
B.use up
C.put up
D.give up
铁碳合金在固态下基本相和组织是什么?