英文現在與過去分詞疑問

She saw her ______ the box at moment.

(a)steal (b)stealing
為什麼不能選steal


She used to drink some _____ water.

(a)boiled (b)boiling
為什麼不能選boiling



thanks!!!!!
Update: She saw her ______ the box at that moment.


saw應該是感官動詞也可以選原形動詞steal吧???
2 answers 2