let和blame用主动表被动的用法

当不定式to let, to blame用作表语时，通常要用主动表被动。如：

The house is to let. 此屋出租。

He said the whole building would be to let. 他说整栋楼都将出租。

My life is ruined and I suppose I only have myself to blame. 我的一生都毁了，我想这只能怪我自己。

If their forces were not involved, then who is to blame? 如果他们的部队没有介入，那么谁应该承担责任?

The writing is clearly on the wall. If we do nothing about it, we shall only have ourselves to blame. 凶兆显而易见。如果我们对此毫无行动，就只能怨自己了。

但是，直接用被动语态也不算错，只是不太普通。如以下两句摘自《朗文英语语法》：

This house is to let / to be let. 此房出租。

Who is to blame / to be blamed? 该怪谁?