Answer:
Remove the comma after watch in sentence 4.
Step-by-step explanation:
Given a paragraph.
A revision is need to be made in the this paragraph.
The first three sentences are correct.
In sentence (4),
the comma needs to be removed after watch in sentence 4.
So,
sentence (4) can be written as follows:
(4) Then they can watch airplanes take off, land, and taxi down the runway.