Question

Joanna saw... outside the window.​

Answer 1

Joanna saw him outside the window.​

Explanation:

• Joanna saw him outside the window.​
• Now, this is a very simple sentence and is stating something about Joanna.
• According to the sentence, here "saw"  is acting as a noun.  
• The noun "saw" is the past tense of the verb "see" and it has three definite forms present, past, and past participle i.e see, saw, seen.
• When we see something it means we are performing an action.