they go to school by bus.(变成一般疑问)

问题描述:

they go to school by bus.(变成一般疑问)
对了,还有.
It's far.(变成否定句)
we all must the traffic rules.(空格里面填什么)?
we all must the traffic rules.(must后面填什么)?
A.know B.knows C.look

do they go to school by bus?
it is not far
we all must obey the traffic rules