3 sentences

1. 蚕在树叶上结了一个茧。

   cán zài shù​yè shàng jié le yī gè jiǎn.

   The silkworm spun a cocoon on the leaf.

   Source: Dong Chinese Dictionary

2. 蚕已经上山结茧了。

   cán yǐ​jīng shàng shān jié jiǎn le.

   The silkworms have gone onto the frames to spin cocoons.

   Source: Dong Chinese Dictionary

3. 由于长年干农活，他的手上长了厚厚的茧。

   yóu​yú cháng​nián gàn nóng​huó, tā de shǒu shàng zhǎng le hòu hòu de jiǎn.

   Due to years of farm work, he has thick calluses on his hands.

   Source: Dong Chinese Dictionary