A:a
B:until
C:while
D:whe
图所示电路,电源电压为6V,R1=10Ω,R2=20Ω,R3=5Ω,当闭合开关S1后,下列说法不正确的是()
The computer is very useful , but it's ____ expensive for the poor man
生物能够表现出非生物所不具有的生命现象.下列古诗描述的现象中,不包含生命现象的是( )
I wonder if I can ____ (help) you.