3 sentences

1. 这些电线都装在金属导管内。

   zhè​xiē diàn​xiàn dōu zhuāng zài jīn​shǔ dǎo​guǎn nèi.

   These wires are all housed in metal conduits.

   Source: Dong Chinese Dictionary

2. 水分通过植物的导管从根部向上传输。

   shuǐ​fèn tōng​guò zhí​wù de dǎo​guǎn cóng gēn​bù xiàng​shàng chuán​shū.

   Water is transported upward from the roots through the plant's vessels.

   Source: Dong Chinese Dictionary

3. 医生将导管插入了手术后患者的膀胱。

   yī​shēng jiāng dǎo​guǎn chā​rù le shǒu​shù hòu huàn​zhě de páng​guāng.

   The doctor inserted a catheter into the patient's bladder after surgery.

   Source: Dong Chinese Dictionary