definitely

根据现代语言学家的理论，在否定句中，主语以及谓语前面的状语，通常不包括在否定范围(the scope of negation)之内，而起加强否定的作用。句(1)的意思是：It is definite that they don't want it.（他们肯定不需要这件东西。）类似的例子：

1. I really don't know him. 我确实不认识他。

2. He actually didn't sit next to her. 他事实上并没有坐在她旁边。

3. Hurling insults and threats is certainly not fighting. 辱骂和恐吓决不是战斗。

4. She definitely didn't speak to him. 她肯定没有同他说话。

而位于否定词项之后的状语则往往位于否定范围之内，并且很可能成为否定的焦点（the focus of negation）。因此句(2)的意思是：It's not definite that they want it.（他们不一定需要这件东西）。类似的例子：

1. I don't really know him. 我并不真的认识他。

2. We don't actually need sugar at all. 我们并不真的需要吃糖。

3. He didn't actually sit next to her. 他并没有真的坐在她旁边。