language exchange wanted

I had a dream since I was in in highschool. We students in China spend most of our time learning English. Sometimes we make fun of ourselves that we someday will invent some Chinese tests which is so difficult to pass. But that's not my dream. you want to hear more ideas? I'll let you know next time

Chrystalsinging: 

This is a great sentence to practice making into one long, long sentence. All errors, including spacing or spelling, have been highlighted.

I have had a dream since high school that students in China who spend most of our time learning English and making fun of ourselves, would ban together and invent some kind of impossible to pass Chinese test.

But then again, maybe that's not my dream. Do you want to hear more ideas? I would tell you if I were asked. (I add "but then again" because in your first statement, you wrote this was your dream, but here you say it's not your dream. By saying: "But then again", it is like saying, "I was only joking when I said this was my dream.)

The point of my corrections are not to say that what you wrote was incorrect but to help you see how you can connect all of your similiar ideas into one statement.

language exchange wanted

I have had a dream since I was in in high school.  We students in China spend most of our time learning English.  Sometimes we make fun of ourselves, and say that someday we will invent some Chinese tests which is so that are very difficult to pass.  But that's not my dream.  Do you want to hear more ideas?  I'll let you know next time.

我啊，英语比普通话难。