专题:
be good at后面加动词ing形式。be good at，善于。例如，You have to be good at spotting trouble on the way and heading it off.
be good at加名词,介词宾格或名词性短语,很重要的就是如接动词要加动词的ing形式.
如I am good at teaching English.I am good at football.
be good at后面要接名词、动名词或名词/动名词短语，
例句：John is good at swimming and basketball.
It is important that we try to be good at everything we do.
I have a shrill voice. I'll never be good at singing.
I am good at chess, but not checkers.