4 sentences

1. 电磁感应是发电机工作的基本原理。

   diàn​cí gǎn​yìng shì fā​diàn​jī gōng​zuò de jī​běn yuán​lǐ.

   Electromagnetic induction is the basic principle behind how generators work.

   Source: Dong Chinese Dictionary

2. 能量守恒定律是物理学的基本原理。

   néng​liàng shǒu​héng dìng​lǜ shì wù​lǐ​xué de jī​běn yuán​lǐ.

   The law of conservation of energy is a fundamental principle of physics.

   Source: Dong Chinese Dictionary

3. 我们必须坚持马列主义的基本原理。

   wǒ​men bì​xū jiān​chí Mǎ Liè​zhǔ​yì de jī​běn yuán​lǐ.

   We must adhere to the basic principles of Marxism-Leninism.

   Source: Dong Chinese Dictionary

4. 只有通晓了其中的基本原理，才能解决更复杂的问题。

   zhǐ​yǒu tōng​xiǎo le qí​zhōng de jī​běn yuán​lǐ, cái néng jiě​jué gèng fù​zá de wèn​tí.

   Only by mastering the basic principles can one solve more complex problems.

   Source: Dong Chinese Dictionary