第一个对了的，特殊疑问句做宾语从句时，只应该用陈述语序的。比如你问题中的句子I want to know what you were doing at that time.宾语从句是what you were doing at that time.这个句子未做宾语从句之前的语序应该是whatwere you doing at that time?那么对于你后面那个句子I don't know how to answer the question.也是正确的，只是现在从句不是特殊疑问句，而是疑问词+to的结构做的宾语。例如：I don't know where to go.
I don't know what to say.都是一样的道理哈...
同学你的问题不在从句，在语法，时态的问题：第一个问题，引导宾语从句的单词有很多有(when, where ,how ,who, whom. whose. what , which and whether or if).你可以分析出这里两句句子中哪个是主语，哪个是谓语么？然后用我给你的单词开始地方就是引导的宾语从句了。第二个问题，请认真注意时态的问题哦...
