。
She can both ski and skate.
Literal
She [topic-は] skiing also skating also can-do.
The pattern X も Y も ('both X and Y, as well as') uses the inclusive particle も on both items to coordinate them additively. With a positive verb the meaning is 'both X and Y do/are'; with a negative verb it would mean 'neither X nor Y'. The polite できます is the polite present of できる (potential of する). The compact double-も pattern is a Japanese efficiency hack — no need for a conjunction like 'and', the も does the work.