______doubt, I turned to one of my English friends for an answer, only ______myself morePuzzled—I was told that it was the way people behaved.

Tom, you ____ leave all your clothes on the floor like this.

They were afraid to complain about the noise ________ they didn’t want to make an enemy of their neighbors.

Shanghai, the largest city in our country, is _______the east of China and_______the west of Japan.

Where have you _______ these days —I have_______ to Hong Kong with my friends.