4 sentences

1. 这条铁路线贯通南北。

   zhè tiáo tiě​lù​xiàn guàn​tōng nán​běi.

   This railway line connects the north and the south.

   Source: Dong Chinese Dictionary

2. 新建的铁路隧道已经全线贯通。

   xīn​jiàn de tiě​lù suì​dào yǐ​jīng quán xiàn guàn​tōng.

   The newly built railway tunnel has been fully connected.

   Source: Dong Chinese Dictionary

3. 这条高速公路的主线已经全线贯通。

   zhè tiáo gāo​sù gōng​lù de zhǔ​xiàn yǐ​jīng quán xiàn guàn​tōng.

   The main line of this highway has been fully connected.

   Source: Dong Chinese Dictionary

4. 学习要讲究融会贯通，不能死记硬背。

   xué​xí yào jiǎng​jiu róng​huì guàn​tōng, bù néng sǐ​jì​yìng​bèi.

   Learning should focus on achieving a comprehensive understanding, not just rote memorization.

   Source: Dong Chinese Dictionary