5. Keeping the environment clean is very important.

    It’s ……………………………………………………………………………………....

6. They will show the time machine to the public when they finish it.

     The time machine ………………………………………………………………….....

7. He was delighted to receive his aunt’s letter.

     He was delighted that ………………………………………………………………...

8. Old car tires are recycled to make shoes and sandals.

     People …………………………………………………………………………….........

9. I’m very sad that I wasn’t accepted in that group.

    I’m very sad not …………………………………………………………………………

10. I usually stayed up late to do my homework last year, but now I don’t.

    I used …………………………………………………………………………………...