I think she's up to something.
→    뭔가꿍꿍이가 있는것 같아.

[예문]
up to something :꿍꿍이가 있는
예 :The teacher thought Chris was up to something.
선생님은 크리스가 뭔가 감추고있다고 생각했다.

A:Carol is acting strange today, isn't she?
 케롤이 오늘이상해,그렇지않니?

B:Yeah,I think she's up to something.
 그래,뭔가 꿍꿍이가 있는것 같아.