GMAT: like, unlike & as ???

Question

在这两句里，为什么只能用unlike和as? 第一句为什么不能用as that of Rosa Parks, 第二句为什么不能用like that of earlier generation? 1. While Jackie Robinson was a Brooklyn Dodger, his courage in the face of physical threats and verbal attacks was not unlike that of Rosa Parks, who refused to move to the back of a bus in Montgomery, Alabama. 2. According to a recent poll, owning and living in a freestanding house on its own land is still a goal of a majority of young adults, as it was of earlier generation.

Answer 1

第一句：as
是连词，当它不用作“作为。。。。”的意思的时候，后面必须接句子（或省略成分的句子，但是一定是句子）。
而LIKE,UNLIKE是介词，后面可以接名词，名词短语，代词，动名词等。
第二句：gamt里，LIKE，UNLIKE永远不放句尾。
similar
to
永远不放句首。记熟这条，看见这样用的就杀，很稳。