3 sentences

1. 专家组正在全力以赴进行技术攻关。

   zhuān​jiā​zǔ zhèng​zài quán​lì​yǐ​fù jìn​xíng jì​shù gōng​guān.

   The panel of experts is going all out to tackle technical challenges.

   Source: Dong Chinese Dictionary

2. 在这次攻关任务中，王工程师主动申请打头阵。

   zài zhè cì gōng​guān rèn​wu zhōng, Wáng gōng​chéng​shī zhǔ​dòng shēn​qǐng dǎ​tóu​zhèn.

   Engineer Wang volunteered to take the lead in this key task.

   Source: Dong Chinese Dictionary

3. 部队冒着敌人的密集火力，英勇攻关。

   bù​duì mào zhe dí​rén de mì​jí huǒ​lì, yīng​yǒng gōng​guān.

   The troops braved heavy enemy fire to heroically storm the pass.

   Source: Dong Chinese Dictionary