1
a penknife
penknife 是可数名词，复数为 penknives。
He always carries a penknife in his pocket.
他口袋里总是带着一把袖珍折刀。
袖珍折刀
penknives — plural of penknife
先理解核心含义，再看它在真实句子里的用法。
袖珍折刀
a small pocketknife; originally used to cut quill pens
He always carries a penknife in his pocket.
他口袋里总是带着一把袖珍折刀。
小折刀；(广义上)任何口袋折刀。
A small pocketknife; (loosely) any pocketknife.
He opened the parcel with his penknife.
他用袖珍折刀打开了包裹。
She always carries a small penknife in her backpack for camping trips.
她去野营时总是在背包里放一把小折刀。
My grandfather gave me an old penknife with a wooden handle.
我祖父送给我一把木柄的旧袖珍折刀。
penknife 是可数名词，复数为 penknives。
He always carries a penknife in his pocket.
他口袋里总是带着一把袖珍折刀。
表示用工具做某事时，常用 with a penknife。
She cut the string with a penknife.
她用袖珍折刀割断了绳子。
open a penknife 意为打开折刀的刀片。
He opened his penknife to peel the apple.
他打开袖珍折刀削苹果。
Not this
There are two penknifes in the drawer.
Use this
There are two penknives in the drawer.
penknife 以 -fe 结尾，复数要把 f 变为 v 再加 -es，即 penknives；不能因为大部分名词加 -s 就写成 penknifes。
Not this
I bought penknife for camping.
Use this
I bought a penknife for camping.
penknife 是可数名词单数，在句中作宾语时前面需要加冠词 a/an；中文没有冠词，所以学习者容易漏掉 a。
Focus on the distinctions below. Other candidates are kept compact until a reliable usage note is available.
一把小折刀
She always carries a small penknife in her bag.
她包里总带着一把小折刀。
打开袖珍折刀
He opened his penknife to peel an apple.
他打开袖珍折刀削苹果。
小折刀刃
The penknife blade is very sharp.
这把小折刀的刀刃很锋利。
折起袖珍折刀
Remember to fold up the penknife after using it.
用完后记得把小折刀折起来。
随身携带袖珍折刀
In some countries it is illegal to carry a penknife in public.
在某些国家，在公共场合随身携带袖珍折刀是违法的。
Use penknives naturally, then get feedback on meaning, tone, grammar, and phrasing.
Revisit a common error or keep this word in your review list.
把 penknife 拆成 pen(笔)+knife(刀)：想象一支鹅毛笔旁边放着一把削笔尖的小折刀——所以是袖珍折刀。
语域：neutral 常见场景：literary writing、outdoor activities penknife 是中性词，指可折叠的袖珍小刀；多用于书面或文学性描述，日常口语中也可使用。此词没有强烈的语域偏向。
复数形式为 penknives（不规则变化）。
Dictionary facts from ECDICT, WIKTIONARY.