Sally is good at ___(play)the violin.

问题描述:

Sally is good at ___(play)the violin.

Sally is good at _playing__(play)the violin
good at doing sth 擅长于做某事

playing be good at doing sth

at是介词嘛,介词后加v.ing

playing
be good at sth 善于做某事
后面加名词,play 是动词,要变成动名词 playing。

Sally is good at _playing__(play)the violin.
be good at doing sth. 擅长做某事. at 是介词 后加动词ING形式.