We must check this house before decide whether rent ornot 我们必须先查看一下房子再决定租不租
2.
Then decide ifyou want to stick around ornot 然后再决定是去是留
3.
Used in affirmative and negative alternatives ( ? ? ? ) : do you agree ornot ? | do you think he did the right thing 助词表示疑问,用于肯定和否定的选择:你到底同不同意呢? |他这样做好不好呢?