3 sentences

1. 有时候他们的恐惧是正当的。

   yǒu shí​hou tā​men de kǒng​jù shì zhèng​dàng de.

   Sometimes their fears are justified.

   Source: CCMatrix

2. 记住，你的感受是正当合理的。

   jì zhu, nǐ de gǎn​shòu shì zhèng​dàng hé​lǐ de.

   Remember that your feelings are valid.

   Source: CCMatrix

3. 正当他在电脑上工作时，来访者进来了。

   zhèng​dāng tā zài diàn​nǎo shang gōng​zuò shí, lái​fǎng​zhě jìn lai le.

   While he was working on his computer, a visitor came in.

   Source: UM-Corpus: Education