一双鞋160元,一支钢笔8元,买一双鞋的钱可以买多少支钢笔?
160÷8=20(支);
答:买一双鞋的钱可以买20支钢笔.
请用恰当的化学用语填写在横线上:自来水养金鱼时为除去其中少量的余氯,可放入少许大苏打(Na2S2O3•5H2O),大苏打由______种元素组成,其中Na、S、O、H的原子个数比为______
____ the flight to Beijing will be delayed is ____ I’m especially worried about.
A.If; what
B.Whether; that
C.When; that
D.Whether; what