4 sentences

1. 礼堂内气氛庄严肃穆。

   lǐ​táng nèi qì​fēn zhuāng​yán sù mù.

   The atmosphere in the auditorium was solemn and grave.

   Source: Dong Chinese Dictionary

2. 纪念馆内的气氛庄严肃穆。

   jì​niàn​guǎn nèi de qì​fēn zhuāng​yán sù mù.

   The atmosphere inside the memorial hall was solemn and respectful.

   Source: Dong Chinese Dictionary

3. 必须彻底肃清这些流毒。

   bì​xū chè​dǐ sù qīng zhè​xiē liú​dú.

   These pernicious influences must be thoroughly eliminated.

   Source: Dong Chinese Dictionary

4. 肃先生是我们的新老师。

   Sù xiān​sheng shì wǒ​men de xīn lǎo​shī.

   Mr. Su is our new teacher.

   Source: Dong Chinese Dictionary