be good at后面加动词什么形式及用法

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...