A:NH3,H2,CH4
B:PCl5,CO2,H2SO4
C:SO2,SiO2,P2O5
D:CCl4,Na2S,H2O2
It has two red eyes. What is it?
如图所示是甲、乙两物体从同一点出发的位移﹣时间(x﹣t)图象,由图象可以看出在0~4s这段时间内( )
一个因数是6,另一个因数是5,积是____
I still like those good old songs I often listened to ________________ myself in my spare time.