Problem: How does the next paragraph end?

How to do water aerobics 
Get a chlorine resistant bathing suit. 
Water aerobic classes are usually about an hour, so you want to make sure you have a suit that can deal with hour long classes a few times a week. 
You can wear a one or a two-piece suit, but a one piece is probably more comfortable.
A: Some gyms might require that you wear a one piece. If you're taking water aerobic classes at a gym, make sure you find out.

Problem: How does the next paragraph end?

There are riders on their own horses and they are holding sticks as the horse runs on the grass. one of the men
A: reach down with their stick and hits the ball that is on the grass and it goes rolling fast.

Problem: How does the next paragraph end?

How to sell billboard space 
Choose a location for your billboard that will attract buyers. 
If you have not yet had your billboard built, choose a heavily-traveled location. Billboards that are viewable from highways are most likely to be noticed by drivers.
A: Billboards closer to the ground are more likely to be noticed than billboards that are higher up, as drivers are focused on objects that are at windshield height. Billboards that are on the right side of the driver's view are more likely to be seen than those on the left side of the driver's view.

Problem: How does the next paragraph end?

A large group are gathered on a field to play. they
A:
engage in a game together.