3 sentences

1. 这把菜刀的刀刃非常锋利。

   zhè bǎ cài​dāo de dāo​rèn fēi​cháng fēng​lì.

   The edge of this kitchen knife is extremely sharp.

   Source: Dong Chinese Dictionary

2. 这把剪刀的刀刃非常锐利，可以轻松剪开厚厚的纸板。

   zhè bǎ jiǎn​dāo de dāo​rèn fēi​cháng ruì lì, kě​yǐ qīng​sōng jiǎn​kāi hòu​hòu de zhǐ​bǎn.

   The blades of these scissors are extremely sharp and can easily cut through thick cardboard.

   Source: Dong Chinese Dictionary

3. 要把有限的资金用在刀刃上。

   yào bǎ yǒu​xiàn de zī​jīn yòng zài dāo​rèn shàng.

   Limited funds should be used where they are needed most.

   Source: Dong Chinese Dictionary