The train arrived ______ Nanjing ______ 6.00 ______the afternoon of Sep. 13.[ ]

I want to know ________ next week，Mum.—If I know about it, I will tell you at once.

He knew the problem was serious and promised to look into it _____ he reached office.

It’s snowing now. You’d better ____ your car slowly on a snowy day. [ ]

You can hardly imagine the difficulty the woman had________ her children.