whether or not 该不该……

【用法透视】
该句的意思是“是否”相当与"if"，用来表达两可的情况。也可以说"whether or no"。

【支持范例】
1. I'll see whether or not I can persuade him to accept it.
我会试试看能不能说服他接受这一点。

2. He seriously debated whether or not he should charge his tenants extra for the water.
他认真地考虑该不该向房客们收取额外的水费。

3. He could not decide whether or not to return home.
他无法决定该不该回家。

【会话记忆】
A: I don't know whether or not to believe him.
我不知道该不该信他。

B: You can trust him. He always tells the truth.
你可以信任他。他总是说实话的。

A: But it's really too important to me.
但这件事对我实在太重要了。

B: I said you can trust him. You just have to believe it.
我说了，你可以相信他，你也必须要相信。