9 sentences

1. 这种李子的内核非常坚硬。

   zhè zhǒng lǐ​zi de nèi​hé fēi​cháng jiān​yìng.

   The pit of this type of plum is very hard.

   Source: Dong Chinese Dictionary

2. 地壳的下层主要是由坚硬的岩石组成的。

   dì​qiào de xià​céng zhǔ​yào shì yóu jiān​yìng de yán​shí zǔ​chéng de.

   The lower layer of the Earth's crust is primarily composed of hard rock.

   Source: Dong Chinese Dictionary

3. 这台高速切割机安装了金刚磨头，非常坚硬。

   zhè tái gāo​sù qiē​gē​jī ān​zhuāng le jīn​gāng mó​tóu, fēi​cháng jiān​yìng.

   This high-speed cutting machine is equipped with a diamond grinding head, which is extremely hard.

   Source: Dong Chinese Dictionary

4. 这种植物的种子外面包着一层坚硬的外衣。

   zhè zhǒng zhí​wù de zhǒng​zi wài​miàn bāo zhe yī céng jiān​yìng de wài​yī.

   The seeds of this plant are covered by a hard outer coating.

   Source: Dong Chinese Dictionary

5. 这种金属非常坚硬，普通的工具无法切割它。

   zhè zhǒng jīn​shǔ fēi​cháng jiān​yìng, pǔ​tōng de gōng​jù wú​fǎ qiē​gē tā.

   This metal is extremely hard; ordinary tools cannot cut it.

   Source: Dong Chinese Dictionary

6. 这口铡已经生锈了，切不动那些坚硬的秸秆。

   zhè kǒu zhá yǐ​jīng shēng​xiù le, qiē bù dòng nà​xiē jiān​yìng de jiē​gǎn.

   This straw cutter has rusted and can no longer cut through those tough stalks.

   Source: Dong Chinese Dictionary

7. 这套家具是用高档橡木制成的，质地非常坚硬。

   zhè tào jiā​jù shì yòng gāo​dàng xiàng​mù zhì​chéng de, zhì​dì fēi​cháng jiān​yìng.

   This set of furniture is made of high-grade oak and has a very hard texture.

   Source: Dong Chinese Dictionary

8. 这种石板质地坚硬，常被用来制作房顶的瓦片。

   zhè zhǒng shí​bǎn zhì​dì jiān​yìng, cháng bèi yòng​lái zhì​zuò fáng​dǐng de wǎ​piàn.

   This kind of slate is hard and is often used to make roof tiles.

   Source: Dong Chinese Dictionary

9. 相传古代工匠能在坚硬的红木上录出各种精美的文字。

   xiāng​chuán gǔ​dài gōng​jiàng néng zài jiān​yìng de hóng​mù shàng lù chū gè​zhǒng jīng​měi de wén​zì.

   Legend has it that ancient craftsmen could carve various exquisite characters into hard mahogany.

   Source: Dong Chinese Dictionary