哪些情况后面要加上谓语动词或be动词?

哪些情况后面要加上谓语动词或be动词?
Cats never become submissive as dogs and horses do
Cats never become submissive in the way that dogs and horses do
His earnings were only half the amount as they used to be
You're as tall as him
There are a lot of famous buildings like Eiffle Tower and .
前几个句子后面会有谓语动词,后两个没有,怎么判断要不要加?