4 sentences for 正当 (zhèng​dāng — just when)

1. 正当酷暑，大家都在树下乘凉。

   zhèng​dāng kù shǔ, dà​jiā dōu zài shù xià chéng​liáng.

   In the sweltering heat of summer, everyone is relaxing in the shade of the trees.

   Source: Dong Chinese Dictionary

2. 正当日中，路上的行人都躲在树荫下避暑。

   zhèng​dāng rì​zhōng, lù shàng de xíng​rén dōu duǒ zài shù​yīn xià bì​shǔ.

   At high noon, pedestrians were all hiding in the shade of trees to escape the heat.

   Source: Dong Chinese Dictionary

3. 正当大家欢度春节的时候，他仍然坚守在岗位上。

   zhèng​dāng dà​jiā huān​dù Chūn​jié de shí​hou, tā réng​rán jiān​shǒu zài gǎng​wèi shàng.

   While everyone else was celebrating the Spring Festival, he remained at his post.

   Source: Dong Chinese Dictionary

4. 正当大家听得入迷时，原本悠扬的笛声突然停住了。

   zhèng​dāng dà​jiā tīng de rù​mí shí, yuán​běn yōu​yáng de dí​shēng tū​rán tíng​zhù le.

   Just as everyone was listening in fascination, the melodious sound of the flute suddenly stopped.

   Source: Dong Chinese Dictionary