2. 外语
  3. Scientists have developed a new cancer drug. So far, they have tested it only on 【B1】______ animals. The drug is designed to 【B2

Scientists have developed a new cancer drug. So far, they have tested it only on 【B1】______ animals. The drug is designed to 【B2

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问题 Scientists have developed a new cancer drug. So far, they have tested it only on 【B1】______ animals. The drug is designed to 【B2】______ and kill cancer cells but not healthy cells.
    First, the drug enters the cancer and destroys the supply of blood. Then it releases 【B3】______ to destroy the cancer cells.
    Researchers at the Massachusetts Institute of Technology in Cambridge carried out the study. The 【B4】______ appeared in Nature 【B5】______ . A school news release called the drug an "anti-cancer smart bomb."
    Ram Sasisekharan is a professor at M.I.T. He says his team had to 【B6】______ three problems. They had to find a way to destroy the blood vessels, then to 【B7】______ the growth of new ones. But they also needed the blood vessels to supply chemicals to destroy the cancer.
    So, the researchers designed a two-part "nanocell". The cell is 【B8】______ in nanometers, or one thousand millionth of a meter. 【B9】______ .
    The scientists say it was small enough to pass through the blood vessels of the cancer, but it was too big to enter normal blood vessels. The surface of the nanocells also helped them to avoid natural defenses.
     【B10】______ That cut off the blood supply and trapped the nanocell inside the cancer. Then, the nanocell slowly released chemotherapy drugs to kill the cancer ceils.
     【B11】______ .
【B9】
选项
答案The particle used was two hundred nanometers--much, much smaller than a human hair.
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