4 sentences

1. 部队决定从北面发起主攻。

   bù​duì jué​dìng cóng běi​miàn fā​qǐ zhǔ​gōng.

   The troops decided to launch their main attack from the north.

   Source: Dong Chinese Dictionary

2. 她主攻京剧中的青衣行当。

   tā zhǔ​gōng Jīng​jù zhōng de qīng​yī háng​dang.

   She specializes in the 'Qingyi' role in Peking Opera.

   Source: Dong Chinese Dictionary

3. 他在读研期间主攻软件工程，尤其擅长开发手机应用。

   tā zài dú​yán qī​jiān zhǔ​gōng ruǎn​jiàn gōng​chéng, yóu​qí shàn​cháng kāi​fā shǒu​jī yìng​yòng.

   During his graduate studies, he specialized in software engineering and was particularly good at developing mobile applications.

   Source: Dong Chinese Dictionary

4. 助攻部队成功牵制了敌人的侧翼，配合主攻部队完成合围。

   zhù​gōng bù​duì chéng​gōng qiān​zhì le dí​rén de cè​yì, pèi​hé zhǔ​gōng bù​duì wán​chéng hé​wéi.

   The supporting troops successfully pinned down the enemy's flanks, helping the main force complete the encirclement.

   Source: Dong Chinese Dictionary