be thought of as和 be considered as 和 be seen as

作为 “……被视为/被看作……"的语义上讲，总体上3个表达一样。
1. We think of Deng Xiaoping as a great leader.
   Deng Xiaoping is thought of as a great leader (by us). as 不可省略。
2. We see Deng as a great leader.
  Deng is seen as a great leader (by us).  as 不可省略。
3. We consider Deng (to be/ as) a great leader.
   Deng is considered (to be/ as) a great leader (by us)
相对而言，3的用法多样些，灵活些。
  类似还有：regard...as.../ view...as.../ treat...as.../ look on ...as...,etc.
体现了语言的丰富多样性，就词义而言，可以随便用，相互替换。