To show our respect, we usually have to take our gloves off _____ we are to shake hands with.
The message is very important, so it is supposed _______ as soon as possible.
Visiting _______ Great Wall is ________ unforgettable experience to me.
---- Do you surf the Internet a lot? ---- Well,_______, I’m too busy with work to surf the Net.
with so much homework to do,David told his sister_____so much noise.
it was because of his kind nature _______I fell in love with Peter.