11. Up went the prices, ____.

(A) down the living standard came (B) the living standard came down (C) down came the living standard (D) came down the living standard

12. He burned all the important documents ____ that they should fall into the enemy´s hands.

(A) unless (B) so (C) until (D) for fear

13. Although he is more serious ____ his studies than I am, my grades are better than his.

(A) with (B) about (C) for (D) at

14. They were just going to give up the question, ____ suddenly they found the answer.

(A) until (B) unless (C) after (D) when

15. Thinking that you know ____ in fact you don´t is a disastrous mistake.

(A) what (B) that (C) when (D) however

16. Aluminium as well as most metals ____.

(A) is a good conductor (B) are good conductors (C) is a good insulator (D) are good insulators

17. Yesterday our professor gave us a ____ assignment.

(A) twenty pages (B) twenty-page (C) twenty-pages (D) twenty page

18. A great effort must still be made ____ the ideas canbe turned into really.

(A) before (B) after (C) then (D) which

19. We have ____ various approaches to the problem.

(A) tried on (B) tried for (C) tried out (D) tried with

20. On entering another country, a tourist will have to ____the Customs.

(A) pass through (B) pass by (C) pass over (D) pass for

答案：C D B D A     A B A C A