86. What is the passage mainly concerned about?

1. New weapon to fight cancer.
2. Chemical modifications to the virus.
3. Gene therapy to cancers.
4. Gene therapy of virus therapy.

87. Which of the following statements is NOT true according to the passage?

1. Cancer Research UK is quite hopeful about Professor Seymour's work on the virus therapy.
2. Cancer's Achilles' heel refers to the fact that virus may stay safely in a tumor and replicate.
3. To infect the cancer cells, a good deal of viruses should be injected into the tumor.
4. Researches on animals indicate that virus could be used as a new way to treat drug-resistant tumors.

88. Information about researches on viruses killing tumor cells can be found ____.

1. on TV
2. in magazines
3. on internet
4. in newspapers

89. To treat tumors spreading out in body, researchers try to ____.

1. change the body's immune system
2. inject chemotherapy drugs into bloodstream
3. increase the amount of injection
4. disguise the viruses on the way to tumors

90. When the chemical modified virus in tumor replicates, the copies ____.

1. will soon escape from the tumor and spread out
2. will be wiped out by the body's immune system
3. will be immediately recognized by the researchers
4. will eventually stop the tumor from spreading out

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