Swimming Strokes by Lee Carroll

Paragraph 4: One of the most easiest strokes for people who are just learning to swim are the backstroke because the swimmer does not put their faces in the water. Your nose and mouth stay above the water, and they can breathe naturally. To do a backstroke, lie supine in the water, do a flutter kick to propel you through the water, and move your arms backward though the water in a windmill fashion to pull yourself. This stroke may seem comfortable and it is easy to do, but it has one major drawback: You couldn't see where you are going. How many errors are there in paragraph 4 relating to subject-verb agreement, parallelism, and pronoun-antecedent agreement because the errors in this passage range from 0 to 3 errors and nothing more than 3 errors?

I found errors such as

just learning to swim are
does not put their faces
and they can breathe naturally
it is easy to do
You couldn't see where

Are these correct?

http://www.jiskha.com/display.cgi?id=1300893030