see sb doing sth 看见某人做某事(其中一部分过程)如:
When I passed her room,I saw her cleaning her room.(看到一部分)
see sb do sth 看见某人做某事(全部过程或全过程持续时间很短)如:
I saw him pick an apple.(pick an apple持续时间很短)
I saw him go into the room(强调全部过程)
see sb do sth 改成被动为:sb be seen to do sth.
see sb to do sth是不符合英语的表达的.