Answer:
10 sentences with coordinating conjunctions:
I need to go to the store, but I'll do it tomorrow.
She loves to dance, and she's been taking classes for years.
Jason forgot to bring his jacket, so he's very cold.
They went to the beach for a swim, yet the water was too cold.
I want to go hiking, or I could stay at home and read a book.
We can go to the park, but we need to be back by three.
She's not feeling well, yet she still came to work.
I want to visit my family and go on a road trip this summer.
I hate the cold, but I love skiing.
You can come with us, or you can stay here and relax.
10 sentences with subordinating conjunctions:
Because I'm tired, I'm going to bed early tonight.
Although it was raining, we still played outside.
Even if it's expensive, I want to buy a new phone.
Since it's hot outside, we should go for a swim.
Unless you study harder, you won't pass the test.
Whenever she sees a dog, she gets excited.
Before I go to work, I have to drop off the kids at school.
As soon as I finish this project, I'm going on vacation.
Since he's allergic to seafood, we can't go to that restaurant.
In case of an emergency, dial 911.
Note: coordinating conjunctions join two independent clauses, while subordinating conjunctions join a dependent clause to an independent clause.