竖式计算,第三题要验算.
147÷21
264÷66
720÷68.
(1)147÷21=7
(2)264÷66=4
(3)720÷68=10…40
_____ the watch and see if you can find out what’s wrong with it.
A.Pack up
B.Break down
C.Dig out
D.Take apart
白芷的化学成分主要为()
A.去氢延胡索甲素
B.延胡索乙素
C.挥发油
D.香豆素类
E.生物碱类