When you use the particle 도 with a noun, you do not use the particles that would mark that same noun as topic (은/는), subject (이/가), or direct object (을/를); notice how 도 takes the place of those particles:
- 나는 미국사람이에요.
I’m an American.
나도 미국사람이에요.
I’m an American, too. - 담배 있어요?
Have you a cigarette?
불도 있어요?
Have you a light, too? - 책을 읽어요.
I read books.
잡지도 읽어요.
I read magazines, too.
This means that some sentences with 도 are ambiguous out of context: 애기도 봐요 can mean either The baby sees it (or him, her etc.), too or (She etc.) sees the baby, too. You can clear up the ambiguity by adding context: 어머니가 애기도 봐요 The mother sees the baby too, 어머니를 애기도 봐요 The baby sees the mother, too. You can, however, use 도 after any of the other particles. For example, 학교에서도 means at school, also or from school, also; 김선생님한테도 means to Mr. Kim, too and so on.
Two occurrences of 도 in the same Korean sentence often correspond to English both. . . and. . ., or in a negative sentence (which you will learn how to do in Lesson 8.1.), (not) either. . . or. . .:
- 아침에도 밤에도 일해요.
I work both in the morning and at night. - 화장실에는 휴지도 수건도 없어요.
There is neither toilet paper nor a towel in the bathroom.