在密闭容器中于一定条件下进行下列反应：2SO₂+O₂⇌2SO₃当到达平衡时通入¹⁸O₂，再次平衡时，¹⁸O存在于（　　）

在右栏中找出左栏问题的答语.

①What club does he want to join? ____   A. He's reading a book.

②Are you using the computer? ____      B. I like cats.

③What animals do you like?____        C. No, I don't.

④Can he play the guitar?____         D. Because they are friendly.

⑤How do they get to school? ____      E. They are from China

⑥What time does he go to bed? ____  F. He wants to join the music club.

⑦Why does he like dogs? ____       G. Yes, I am.

⑧Where are pandas from? ____     H. No, he can't.

⑨What's he doing now? ____      I. They ride their bikes.

⑩Do you have to clean your room? ____  J. At 9:30.