Suppose A equals B.
假定 A等于B。

Let us suppose another planet with conditions similar to those on the earth.
讓我們假定另外有一個具有和地球上相似條件的行星。

Assuming this to be true ...
假定這是真的 ...。

You assume his innocence before hearing the evidence against him.
在未聽到對他不利的證言之前， 你假定他是無罪的。

The new discoveries have falsified that hypothesis.
新的發現已證明那個假定是無根據的。