===========CORRECTED SENTENCES===========

When I swim in the beach, I will wear a swimsuit.

I will play with friends.
                                                          

               ===========REMINDERS===========

1.
Eric: When I swim in the beach, I wear a swimsuit.
Correct: When I swim in the beach, I will wear a swimsuit.
Explanation: Since you are talking about what you will do in the future, use the word WILL to connote the idea well. We add will before a verb to use it in its future tense.

2.
Eric: I play with friend friendly.
Correct: I will play with friends.
Explanation: Practice using will in your sentences whenever you are talking about things that you will do in the future. You don't have to use the adjective friendly because in general, your friends are friendly. Use the plural form of the subject if you're talking about more than one entity.

Eric, Gabe! I am so happy you were able to make your homework and I can observe that you are improving as each day pass by. Anyway, please study more and work hard especially on your sentence construction. You can do it, Eric! See you next week! Have a happy weekend~ Bye!

- T. Rose