My sister is good skateboarding. And she swims well too.A. forB. atC. withD. in

问题补充：

My sister is good skateboarding. And she swims well, too.

A. for

B. at

C. with

D. in

答案：

A. for

(答案→)B. at

C. with

D. in

解析：介词辨析。For为了；at在某一点；with带有，伴随；in在里面。句意：我的姐姐擅长滑板运动。她也很会游泳。Be good at doing sth,意思为擅长····意思。故选B。