18.擅长，在…...方面做得好

　　be good at=do well in

　　She is good at chemistry.=She does well in chemistry.

　　她擅长化学。

　　Niuniu is good at playing the violin.=Niuniu_does well in playing the violin.

　　妞妞擅长弹钢琴。

　　Lucy and Lily are twin girls.Lucy is better at dancing tha nLily，but Lily does better in singing than Lucy.