26. You have to know __________ you're going if you are to plan the best way of getting there.
根据分析可知:You have to know后面是一个宾语从句。宾语从句的连接词有连接代词和连接副词,连接代词有:who、whom、whose、which、that,在句子中担任主语、宾语、定语或者表语,连接副词有:when,where,why,how,在句子中担任状语成分。
【解析思路】you're going if you are to plan the best way of getting there.是一个完整的句子,所以所以应该用连接副词来引导从句。句意:如果你已经计划好去那里的最佳方案,你必须知道你将要去哪里。故选C。
对于从句引导词的辨析。