1.A:But no one saw me hit the car.
B: Even if no one saw you, leaving a note is right thing to do.
2.A:You two know each other?
B:Yes.Richard,I mean Rick, works part-time in my office.
想請問知識大大們,為什麼上述兩句B的的對話一個是逗號後使用Ving(leaving),而另一句卻是使用原形V(work)呢?兩句是使用不同文法嗎?如果是使用不同文法可以分別解釋一下嗎?謝謝: )