2 sentences

1. 老师拿着扩音器在操场上维持秩序。

   lǎo​shī ná zhe kuò​yīn​qì zài cāo​chǎng shàng wéi​chí zhì​xù.

   The teacher used a megaphone to maintain order on the playground.

   Source: Dong Chinese Dictionary

2. 老师拿着扩音器站在操场中央，指挥学生们集合。

   lǎo​shī ná zhe kuò​yīn​qì zhàn zài cāo​chǎng zhōng​yāng, zhǐ​huī xué​sheng men jí​hé.

   The teacher stood in the middle of the playground with a megaphone, directing the students to assemble.

   Source: Dong Chinese Dictionary