我的英语期待您的拯救~关于名词性定语从句的

我的英语期待您的拯救~关于名词性定语从句的下面这些题目是没有语境设定的.左边是我的答案,右边是英语老师给的答案,真心不懂为什么我的答案是错的,希望各位行行好,帮我解释一下错误的原因(why)who caused the accident was a man lying on the ground.(what)whom your daughter loves is clear.(why)that he left his wife cut her to the heart.(how)whether we go there remain to be decided.(that)when your uncle will arrive was not mentioned in his letter.为什么下面这些可以有多个答案but i forger how/why/where the accident happened last sunday (为什么这个不可以用whether?）还希望您可以为我提供一些做名词性定语从句的诀窍,现在这个老师的英语水平太高了,我听不懂她的课,希望你们可以帮到我!