在探究“植物对空气湿度的影响”时,在裸地测量三次后求平均值,这样做的目的是 。
减少误差
实验常常要重复多次,取平均值,减少误差,得到比较可靠的结果。
A quarrel _____ last Sunday, and he _____ his family. [ ]
A. was broken out; broke away
B. broke out; broke away from
C. was broke out; broke away from
D. broke out; broke away
目前常用的多用户操作系统为 ______ 。
A.UNIX
B.DOS
C.Windows NT
D.UNIX和Windows NT