3 sentences

1. 他正在教我如何操作这台起重机。

   tā zhèng​zài jiāo wǒ rú​hé cāo​zuò zhè tái qǐ​zhòng​jī.

   He is teaching me how to operate this crane.

   Source: Dong Chinese Dictionary

2. 工人们正在用起重机提升沉重的货物。

   gōng​rén men zhèng​zài yòng qǐ​zhòng​jī tí​shēng chén​zhòng de huò​wù.

   Workers are using a crane to lift heavy goods.

   Source: Dong Chinese Dictionary

3. 工人们正在操作起重机吊起沉重的钢梁。

   gōng​rén men zhèng​zài cāo​zuò qǐ​zhòng​jī diào​qǐ chén​zhòng de gāng​liáng.

   Workers are operating a crane to lift heavy steel beams.

   Source: Dong Chinese Dictionary