The giant knocks the wall around his garden. ( )
A:off
B:down
C:on
— The computer is working all the time.
— Sorry. I have forgotten ______.
2016年5月9日19时12分左右,“水星凌日”的天象于本世纪第三次出现.如图所示,水星如一颗小黑痣从太阳“脸上”缓慢爬过.它的形成与下列光现象原理相同的是( )