题目

To ________ the river means to make the river dirty.A.protect B.pollute C.provide 答案：【答案】B【解析】句意：污染河流意味着河流会变脏。考查动词词义辨析。protect 保护；防护；pollute 污染；provide 提供；供应。由“make the river dirty”可知此空应填污染。故选B。 The doctors and nurses were very tired, ________ they still went on working. A．so B．and C．or D．but