3 sentences

1. 正门上方挂着一块匾额。

   zhèng​mén shàng​fāng guà zhe yī kuài biǎn é.

   A horizontal inscribed board hangs above the main entrance.

   Source: Dong Chinese Dictionary

2. 我们在办公大楼的正门等候经理。

   wǒ​men zài bàn​gōng dà​lóu de zhèng​mén děng​hòu jīng​lǐ.

   We are waiting for the manager at the main entrance of the office building.

   Source: Dong Chinese Dictionary

3. 远远望去，皇宫正门前的两座魏十分高大。

   yuǎn​yuǎn wàng qù, huáng​gōng zhèng​mén qián de liǎng zuò wèi shí​fēn gāo​dà.

   Looking from afar, the two watchtowers in front of the main gate of the imperial palace are very tall.

   Source: Dong Chinese Dictionary