3 sentences for 心眼 (xīn​yǎn — shrewdness)

1. 他心眼多，在生意场上从来没吃过亏。

   tā xīn​yǎn duō, zài shēng​yi chǎng​shàng cóng​lái méi chī guo kuī.

   He is very shrewd and has never lost out in business.

   Source: Dong Chinese Dictionary

2. 他这人做事没准，你最好多留个心眼。

   tā zhè rén zuò​shì méi​zhǔn, nǐ zuì hǎo duō liú gè xīn​yǎn.

   He is unpredictable; you'd better be a bit more cautious.

   Source: Dong Chinese Dictionary

3. 那人性格极奸，你平时要多留个心眼。

   nà rén xìng​gé jí jiān, nǐ píng​shí yào duō liú gè xīn​yǎn.

   That person is extremely treacherous; you should be more cautious.

   Source: Dong Chinese Dictionary