8 sentences

1. 这道几何题很难解。

   zhè dào jǐ​hé tí hěn nán jiě.

   This geometry problem is very hard to solve.

   Source: Dong Chinese Dictionary

2. 层论是代数几何的重要基础。

   céng lùn shì dài​shù jǐ​hé de zhòng​yào jī​chǔ.

   Sheaf theory is an important foundation of algebraic geometry.

   Source: Dong Chinese Dictionary

3. 三角形和正方形都属于几何图形。

   sān​jiǎo​xíng hé zhèng​fāng​xíng dōu shǔ​yú jǐ​hé tú​xíng.

   Triangles and squares are both geometric shapes.

   Source: Dong Chinese Dictionary

4. 球体和圆柱体都是常见的几何形状。

   qiú tǐ hé yuán​zhù​tǐ dōu shì cháng​jiàn de jǐ​hé xíng​zhuàng.

   Spheres and cylinders are common geometric shapes.

   Source: Dong Chinese Dictionary

5. 这道几何题很难，我不知道该如何求解。

   zhè dào jǐ​hé tí hěn nán, wǒ bù zhī​dào gāi rú​hé qiú​jiě.

   This geometry problem is very difficult; I don't know how to solve it.

   Source: Dong Chinese Dictionary

6. 解析几何是数学中一个非常重要的分支。

   jiě​xī jǐ​hé shì shù​xué zhōng yī gè fēi​cháng zhòng​yào de fēn​zhī.

   Analytic geometry is a very important branch of mathematics.

   Source: Dong Chinese Dictionary

7. 请问老先生春秋几何？

   qǐng​wèn lǎo xiān​sheng chūn​qiū jǐ​hé?

   May I ask how old you are, sir?

   Source: Dong Chinese Dictionary

8. 对酒当歌，人生几何？

   duì​jiǔ​dāng​gē, rén​shēng jǐ​hé?

   Sing while having wine, for how long does life last?

   Source: Dong Chinese Dictionary