He did all this ______ silence,and very rapidly.( )
A.atB.inC.withD.of
By the end of last week, she______in the west of China for two months helping the homeless children.
Ken was so busy when we saw him, because he _______ a speech the next day.
--- What did he tell you just now?--- He said that ____________ tomorrow morning.
By the time Dave reached the small boat, a thick white fog _______ over the surface of the water.
The teacher told the kids that light ________ faster than sound.