Police are warning the public to be on the alert for suspicious packages.

警方警告公众要警惕可疑包裹。

《牛津词典》

He warned the public to be vigilant and report anything suspicious.

他告诫公众要保持警惕，报告任何可疑情况。

《柯林斯英汉双解大词典》

I have good reason to be suspicious.

我的怀疑有充分理由。

《牛津词典》

In efforts to repress any revolutionary fervor in the past few years, Iran has deemed large gatherings of people to be suspicious.

VOA: standard.2010.06.15

You can run into issues of things like overflow, underflow, with floating point numbers and when you see a whole bunches of ones, it's particularly a good time to be suspicious.

来看看哪儿会出问题，你可能会碰到浮点数中的溢出和下溢问题,当你碰到一系列这种问题后，可能就会适时的开始怀疑结果的正确性。

麻省理工公开课 - 计算机科学及编程导论课程节选

And security officials are encouraging passengers to be observant and report any suspicious activity.

VOA: standard.2009.12.26

But law enforcement and federal officials are urging everyone to be vigilant to anything suspicious and to report anything if you see it.

CNN: Jeanne Meserve: Cities respond differently to terror alert

Asians tend to be suspicious of the Democrats' inclination to place political idealism before hard realities, as well as their penchant for protectionism.

CNN: Election Watch

But if the data needed to show who had really fathered a child were being collected routinely for other purposes, it would be hard to deny suspicious men the right to check that the infant they were helping to bring up was really theirs in the first place.

ECONOMIST: A survey of the human genome