--There             so many foreigners in the streets these days.-- They might be runners in the Yellow River Estuary (入海口，河口) International Marathon.

She is very happy ______ she has got many good friends.

The little girl felt upset _________ her pet dog died.

Practice more, ________ you’ll do better in playing chess.

Learning to write is learning to think. You don’t know things clearly _______ you can write them down.