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

Scientists have developed a new cancer drug. So far, they have tasted 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 tasted 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 caned the drug an "anti-cancer smart bomb."
    Ram Sasisekharan is a professor at M.LT. Ha 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, tile 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 halped, 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 cells.
    【B11】______
【B9】
选项
答案The particle used was two hundred nanometers—much, much smaller than a human hair.
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