If you have difficulty     something，wearing red     it easier for you to take action．

Liu Chang said that joining the English club at school was the best way ______ her English.

 —We must stop ________ plastic bags (塑料袋).—You’re right. It’s bad for our environment(环境).

Mr. Wu came into the  classroom ,         a book in his hand.

Frank asked his father ____ a new bike for him and his father said OK.