1。 Now it is divided into adverbials: we are all sitting in the lecture hall, but I am taking care of the professor.

2. Now it is divided into object and complement: indicating the action that is happening or repeating. For example:

I saw the girl crossing the busy street.

3. Now it is divided into post-attributive: when a phrase is used as an attributive, it is often placed after the modified word, indicating that the action is going on or occurs almost simultaneously with the action indicated by the verb, or indicating a regular action or state, such as:

The lady standing over there is our new headmaster.