第6题:[单选题]Walnut trees __________ environment stresses such as drought by producing significant amountsof a substance similar to aspirin. A.turn to B.confirm to C.contribute to D.respond to 参考答案:D 考查动词短语辨析。turn to“转向;变成;求助于;致力于;开始行动”,confirm to“证实”,contribute to“有助于”,respond to“对……反应”。句意为“面对来自环境的压力,例如干旱,胡桃树会释放大量类似阿司匹林的物质”。D项最符合句意。