3 sentences

1. 网络联通非常顺畅，没有任何延迟。

   Wǎng​luò lián​tōng fēi​cháng shùn​chàng, méi​yǒu rèn​hé yán​chí.

   The network connection is very smooth, without any lag.

   Source: Dong Chinese Dictionary

2. 新建的铁路将这两个城市联通了。

   xīn​jiàn de tiě​lù jiāng zhè liǎng gè chéng​shì lián​tōng le.

   The newly built railway has connected these two cities.

   Source: Dong Chinese Dictionary

3. 由于联通的套餐很实惠，我办了一张号卡。

   yóu​yú Lián​tōng de tào​cān hěn shí​huì, wǒ bàn le yī zhāng hào​kǎ.

   Since China Unicom's plans are very affordable, I got a SIM card from them.

   Source: Dong Chinese Dictionary