Every Gerund ends with - ing , so in this sentence we have ‘marooning’. Ths is a verb that acts as a noun.
Answer:
2. might have forgotten to take it with him.
3. he couldn't have run (im not sure about this one sorry D:)
4. must have left them at Donna's house.
5. you should have told me / I would have given you...
(rushes into the house) is an example of stage direction because it is telling the character what to do