33.
(A) extend
(B) extensive
(C) exclusive
(D) excessive

29. A ceremony was held in memory of the firefighter who ______ his life for a little girl last year. (A) saved (B) endured (C) sacrificed (D) commemorated

30. The spy was ______ from the country after he was caught and arrested. (A) relieved (B) banished (C) hibernated (D) involved

31. (A) wreck (B) incident (C) event (D) disaster

32. (A) without a question (B) without a doubt (C) without a scratch (D) without an accident

34. (A) fluttered (B) flattered (C) flirted (D) flared

35. (A) fading out (B) wearing off (C) going off (D) pulling out 

36. What is the main idea of the passage? (A) After two decades of lab research, gene therapy in humans has been successful in treating everything from cancer to Alzheimer's to heart disease. (B) A lot of research in gene therapy has focused on getting a gene to its destination and coaxing it to turn on once inside a cell. (C) Although research has been done on how gene therapy can help treat serious diseases, such a treatment may cause irreversible side effects and unknown consequences. (D) Viral vectors like Trojan horses slip genes into target cells undetected.

37. "Viral vectors" are _______. (A) ways with which viruses genomes are changed (B) viruses used for carrying genetic material into cells (C) the paths through which viruses move (D) immune reactions triggered by viral infection

38. What does the word "trigger" mean in the passage? (A) Activated (B) Shoot (C) Turn off (D) Plug

39. According to the passage, which of the following statement is NOT correct? (A) Genes are unable to move across cell membranes on their own. (B) Gene therapy is still in its early stages. (C) Scientists have made significant progress in taking control of viruses that carry therapeutic genes. (D) Much effort in gene therapy has been spent to deceive cells into accepting foreign genes.