`~rai~`

$\begin{array}{I}16.B\\17.C\\18.B\\19.A\\20.A\\VI.\\\text{1.Penicillin was discovered by Alexander Fleming in 1928.}\\\text{2.The seals at the zoo are fed three times a day.}\\\text{3.Delicious dishes are often cooked by my mother on Saturday.}\\\text{4.The road has been blocked up for an hour by the police after the acident.}\\\text{5.Her parents never allow her to go out at night.}\\\text{6.The securrity guard made the boy stop his car.}\\\text{7.The boss forced his secretary to type a 50-page report.}\\\text{8.If she weren't shy,she would enjoy the party.}\\\text{9.If he had revised all his lesson,he wouldn't have failed the exam.}\\\text{10.Unless you leave me alone,I'll call the police.}\end{array}$

16. B. We have to submit it by Friday 12

17. C. Sorry, I don't know

18. B. Because it is soft and beautiful

19. A. Sure. Just go along this street

20. A. How time flies!

IV.

1. Penicillin was discovered by Alexander Fleming in 1928.

2. The seals at the zoo are fed three times a day.

3. Delicious dishes are often cooked by my mother on Saturday.

4. The road has been blocked up for an hour by the police after the acident.

5. Her parents never allow her to go out at night.

6. The security guard made the boy stop his car.

7. The boss forced his secretary to type a 50-page report.

8. If she weren't shy, she would enjoy the party.

9. If he had revised all his lesson, he wouldn't have failed the exam.

10. Unless you leave me alone, I'll call the police.