3 sentences

1. 请在合同末页加盖公章。

   qǐng zài hé​tong mò yè jiā​gài gōng​zhāng.

   Please stamp the official seal on the last page of the contract.

   Source: Dong Chinese Dictionary

2. 水烧开后，加盖焖五分钟。

   shuǐ shāo​kāi hòu, jiā​gài mèn wǔ fēn​zhōng.

   After the water boils, cover it and simmer for five minutes.

   Source: Dong Chinese Dictionary

3. 他在旧房子的楼顶加盖了一间阁楼。

   tā zài jiù fáng​zi de lóu​dǐng jiā​gài le yī jiān gé​lóu.

   He built an additional attic on the roof of the old house.

   Source: Dong Chinese Dictionary