6 sentences

1. 市中心的人口非常密集。

   shì​zhōng​xīn de rén​kǒu fēi​cháng mì​jí.

   The population in the city center is very dense.

   Source: Dong Chinese Dictionary

2. 墙脚下生长着密集的茨，果实带刺。

   qiáng​jiǎo xià shēng​zhǎng zhe mì​jí de cí, guǒ​shí dài​cì.

   Dense puncturevines grow at the foot of the wall, and the fruits have thorns.

   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

4. 长江流域是中国人口最密集的地区之一。

   Cháng Jiāng liú​yù shì Zhōng​guó rén​kǒu zuì mì​jí de dì​qū zhī​yī.

   The Yangtze River basin is one of the most densely populated areas in China.

   Source: Dong Chinese Dictionary

5. 这个街道的人口非常密集，公共服务也做得很到位。

   zhè gè jiē​dào de rén​kǒu fēi​cháng mì​jí, gōng​gòng fú​wù yě zuò de hěn dào​wèi.

   This neighborhood is very densely populated, and the public services are well-managed.

   Source: Dong Chinese Dictionary

6. 考试前，学生们进行了密集的复习。

   kǎo​shì qián, xué​sheng men jìn​xíng le mì​jí de fù​xí.

   Before the exam, the students did some intensive revision.

   Source: Dong Chinese Dictionary