人们普遍感觉到有了疗效，这样我们就很不好确定一种药物本身的实际疗效。

Ubjects typically know they are getting some kind of treatment, and so we may rarely be able to measure the actual effects of a drug by itself.

youdao

不过渐进式的修改也会产生过分复杂的代码——因为要应对很多特例情况，而且也不太靠靠——因为不好确定你是否找到了所有的错误。

But incremental corrections can generate code that is unnecessarily complicated-since it deals with many special cases-and unreliable-since it is hard to know if you have found all the errors.

youdao

但我不能确定这样好不好。

I'm not sure whether its such a good idea.

youdao

I don't know if you can see those colors much at all, sorry about that.

我不太能确定你们是否能看清,这些颜色,不好意思

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