But, if a field is fairly simple, you should be able to get some general feeling for whether your answer should be positive, negative or zero just by thinking about which way is my flow going.

但如果流速场很简单的话，大家理应有一种直觉，可以感受出来，结果应该为正为负，还是为零。

youdao

They then cascaded the negative index medium with a positive refractive index medium so that the complete nanostructure behaved as one with an index of refraction of zero.

他们将负折射率材料和正折射率材料级联起来成功实现了零折射率行为的纳米结构。

youdao

Respondents were asked how they would rate their lives on a scale from zero (worst possible) to 10 (best possible), as well as answering a series of questions on positive or negative emotions.

受访者被问到他们将如何给自己的生活评分：量表从0分(可能最糟糕的生活)到10分(可能最美好的生活)；同时还需要回答一系列关于积极或消极情绪的问题。

youdao

The key work variable is zero-sum vs. non-zero sum (both negative-sum and positive-sum).

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This figure also languished close of zero and even turned negative in 1998-2001, but since then it has turned strongly positive for Japan.

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