Someone whose job is welding — joining pieces of metal by heating them until they melt together at the join. Welders work in factories, on ships, on building sites, and on oil rigs. It is a skilled trade: a good welder trains for years, needs a certificate in many countries, and can earn very well, especially for dangerous work like underwater welding.

Someone whose job is welding指的是工作是welding（焊接）的人 — joining pieces of metal by heating them until they melt together at the join也就是把金屬加熱到接合處熔在一起。Welders焊工 work in factories, on ships, on building sites, and on oil rigs在工廠、船上、工地，還有鑽油平台上工作。It is a skilled trade這是一門技術工作: a good welder trains for years一個優秀的焊工要訓練好幾年, needs a certificate in many countries在很多國家還需要證照, and can earn very well而且收入可以很不錯, especially for dangerous work like underwater welding尤其是像水下焊接這種危險的工作。

Note one thing that trips learners up: 'welder' also names the machine, not just the person. 'I bought a welder last week' means you bought the welding equipment. Which one you mean is almost always clear from the sentence — machines get bought and plugged in, people get hired and go home.

Note one thing that trips learners up有件事很容易讓學習者搞混，要注意: 'welder' also names the machine, not just the person「welder」也可以指焊接機，不只是指人。'I bought a welder last week'「I bought a welder last week」 means you bought the welding equipment意思是你買了焊接設備。Which one you mean is almost always clear from the sentence你指的是哪一個，通常從句子就看得出來 — machines get bought and plugged in機器是被買、被插電使用的, people get hired and go home人則是被雇用、下班回家的。

English does this with a lot of -er words (a cooker, a printer, a driver in a golf bag), so it is worth noticing the pattern rather than learning each case separately.

English does this with a lot of -er words英文有很多-er結尾的字都是這樣 (a cooker, a printer, a driver in a golf bag)（像a cooker爐具、a printer印表機、高爾夫球袋裡的a driver球桿）, so it is worth noticing the pattern rather than learning each case separately所以值得注意這個規律，而不是一個一個死背。