I think it will be long ______ the influence of Sanlu Milk Powder incident dies down

When she was in trouble, I did what I could to help her．__________ my help, she wrote me a letter of thanks

下列各句中，加点的成语使用正确的一项是（ ）

We can often see ice here in winter because the temperature usually stays__________ zero.

How do you like the popular TV programme The Voice of China in Zhejiang TV Station—Ha ha! That’s my favourite. I’ve never seen one.