— What a pity! You missed the beginning of the movie and it for 10 minutes.— Oh, a traffic jam!
A:began
B:stated
C:has been on
D:has been off
设NA表示阿伏加德罗常数,下列说法正确的是( )
读读做做。
今天星期天,我来做家务。先来擦桌子,再来拖地板。妈妈看着我,开心地笑了,爸爸说我长大了。