Liu Xiang’s talent for running and his ability to learn from his experiences________greatly to his many successes in sports.

 —He thinks that girls are smarter than boys when it comes to learning English. —But two years ago he thought_______. 

brown

To play better, all the players have to know their ___________ and weaknesses.

A clean environment can help the city bid for the Olympics, which ________ will promote its economic development.