3 sentences

1. 一点尘埃，何以为毒？

   yī​diǎn chén'āi, hé​yǐ wéi dú?

   How can a bit of dust be poison?

   Source: OpenSubtitles

2. 既然事实如此，你何以不信？

   jì​rán shì​shí rú​cǐ, nǐ hé​yǐ bù xìn?

   Since the facts are as they are, why don't you believe it?

   Source: Dong Chinese Dictionary

3. 你何以证明这张钞票不是伪造的？

   nǐ hé​yǐ zhèng​míng zhè zhāng chāo​piào bù shì wěi​zào de?

   How can you prove this banknote is not a counterfeit?

   Source: Dong Chinese Dictionary