第23题: [单项选择]Scientists are expected to carry out thoroughgoing studies to back up claim's made concerning new drugs. A. support B. elevate C. investigate D. challenge 参考答案:A 答案解析:画线词back up,在这里的意思是:依靠,支持;其近义词为A support。辨义:A support支持。辨义:通过语义判断,到分辨词汇可分辨义:A.elevate;B.提高;C.investig