比x多20的数是5的多少倍?
(x+20)÷5
=x5+4
答:比x多20的数是5的x5+4倍.
I had never heard an English word ________ before I went to junior high school. [ ]
A. speak
B. to speak
C. speaking
D. spoken
咖啡因的化学结构式为()
A.A
B.B
C.C
D.D
E.E