第21题: [单项选择]An investigation that is ______ can occasionally yield new facts, even notable ones, but typically the appearance of such facts is the result of a search in a definite direction. A. timely B. unguided C. consistent D. subjective 参考答案:B 答案解析:(unguided无向导的)。句意为:无向导的调查偶尔会产生新的论据,甚至是值得注意的论据。但是,这些论据的出现通常是按照一定方向搜索的结果。A.timely及时的;C.consistent坚持的;D