【简答题】根据短文内容,从下面表格中选择正确的选项填入横线空格处。 A. Scientists are still working on testing them. B. So some clever farmers have solved (解决) the watermelon problem. C. Doctors might be able to use vegetables to fight can...
【简答题】【C1】______ nearly a hundred years of powered flight, scientists are still trying to figure out how birds fly. Researchers have learned that the slapping noise pigeons make when they suddenly take off ...