adj.可疑的，有问题的，未必准确(或正确)的，可能不诚实(或不道德)的，别有用心的

The evidence for his guilt is questionable at best.
对他有罪的证据充其量是可疑的。
Her explanation for the accident was questionable, to say the least.
她对事故的解释，至少可以说是有问题的。
The company's financial statements are questionable, leading to an audit investigation.
公司的财务报表存在问题，导致了审计调查。
His memory of the event is questionable due to his advanced age.
由于年纪大，他对事件的记忆可能有问题。
The authenticity of the artwork is questionable by art experts.
这件艺术品的真实性受到了艺术专家的质疑。
The witness's testimony seems questionable given the inconsistencies in their story.
鉴于证人陈述中的不一致，他们的证词似乎值得怀疑。
The diet fad promises quick results, but its safety is questionable.
这种饮食减肥法声称效果快，但其安全性却令人质疑。
The defendant's claims of innocence are questionable, given the overwhelming evidence against them.
被告声称自己无罪的说法，在大量不利于他的证据面前显得可疑。
The product's durability is questionable, as many customers have reported early failures.
产品的耐用性存在问题，因为许多客户报告过早期故障。
The decision to postpone the project is questionable, considering the urgent need for completion.
在考虑到项目急需完成的情况下，推迟决定显得不太合理。