单选题5. Young scientists ______ that existing scientific knowledge is not nearly so complete, certain and unalterable as many textbooks seem to imply.
【正确答案】
C
【答案解析】 年轻科学家应尽快意识到现有的科学知识绝不像许多教科书所暗示的那样全面、必然或一成不变。 固定搭配题。“cannot...too...”结构表示“怎样……也不过分；应尽量……；越……越好”之意。例如：You cannot praise the book too much. (这本书很值得大加赞扬。)类似用法还有“can never...too...”，故本题答案为C。