!!!在线等英文翻译!!!!!!!!

The reason why you think I am still alive is that you are not told (that) I am dead. (时态必须一致，另：活于死，这里都是状态，而不是动作，因此都因该用系表结构）
or
That you think I am still alive is because you are not told (that) I am dead.
(that 作现行主语，谓语is。。。）

没用no one told you的原因是，主句从句的主语一致，更符合英文习惯，读起来更顺。
不用consider是因为，这个事情不用有理智地去思考，think含有主观的认为含义，think更恰当。

To think I am still alive is because no body told you about my death!

The reason why you consider me alive is that nobody tells you I am dead.

The reason why you think I'm still alive is that no one has told you I've died.

You consider me alive because you haven't been told that I've been dead.

(注：话是放在这了，但是一个能说这句话的人还能是活的吗？如果不是活的，还能说出这句话吗？）

Why did you think that I'm still alive is because no one told you that I've been dead.

感觉像是电影里的情节，是违背常理的。

其他人的翻译都不错，不过貌似时态上有些错误。

如果是死者的灵魂说给另一人听的，那就要用did，因为另一人认为死者还活着的错误想法在死者以死亡身份告诉另一人时已经过去。

而中间的“I'm still alive”仍要用现在时是因为那是另一人想法的内容。死者不过是在重新陈述一下。

至于最后，就好理解了，“我已经死了”是死者就自己现在已死的状态而言的。