Learn Hardcore Korean: jeonjareinjiro eumsik de-umyeon sigani jeoryakdwaeyo. - Using the microwave to heat food saves time.

전자레인지 means “microwave.” The particle -로 marks the means or instrument, so 전자레인지로 means “by/with a microwave.” We use 로 (instead of 에서) when highlighting the tool or method.

Why don’t we use 에서 instead of 로?

The particle 에서 indicates the location where an action occurs, whereas 로 indicates the instrument or method. In 전자레인지로 음식 데우면, the focus is on “using” the microwave, so 로 is the correct choice.

Could we say 전자레인지에 음식을 데우면 instead?

You could, but that emphasizes “heating in the microwave” (location). It’s grammatically correct but slightly different in nuance. Also, dropping the object particle (음식을 → 음식) sounds more natural in spoken Korean.

What does 데우면 mean?

데우다 = “to warm up; to heat (food)”
-으면 = conditional ending “if/when …”
So 데우면 = “if you heat (it).”

Why is 음식 not marked with a particle like -을/를?

In conversational Korean, particles are often dropped when the meaning is clear. Omitting -을/를 in (음식을) 데우면 makes the sentence more natural and less stiff.

Why is there no explicit subject in this sentence?

Korean often omits subjects (and objects) when they’re understood from context. Here it’s a general statement (“if you heat food ...”), so “you” or “one” is implied and not stated.

What does 시간이 절약돼요 literally mean?

시간 = “time” + subject marker -이
절약되다 = “to be saved; to be economized”
So 시간이 절약돼요 literally means “time is saved,” often translated as “(you) save time.”

Why is it 절약돼요 instead of 절약해요?

절약하다 = active verb “to save,” so 시간을 절약해요 = “you save time.”
절약되다 = passive/intransitive “to be saved,” so 시간이 절약돼요 = “time is saved.”
Both express saving time but from different grammatical perspectives.

How did 되어요 contract to 돼요?

There’s an irregular contraction in Korean: -되다 + -어요 becomes -돼요. So 절약되어요 contracts to 절약돼요 for smoother pronunciation.

What politeness level is used with the -요 ending?

The -요 ending indicates the polite informal style (also called 해요체). It’s appropriate for everyday polite conversation—polite but not overly formal.