I. Follows nouns; indicates such meanings as “and” and “with,” and sets off names.
Aran-san to Pōru-san wa Furansu-jin desu.
Alain and Paul are French.
Shiroi yuri to akai bara no hana o kaimashō.
Let’s buy some white lilies and red roses.
2. Indicates a comparison or contrast: “and” or (when a choice is asked for) “or.”
Note: In this usage, to must follow each of the nouns.
Kono kaisha to sono kaisha to de wa, shihon-kin ga chigaimasu.
This company and that company have different amounts of capital.
Ringo to mikan to dochira ga suki desu ka.
Which do you like better, apples or mandarin oranges?
3. “Together, with.”
Shachō wa buchō to shokuji o shite imasu.
The company president is eating out with the division manager.
Ashita kono mondai ni tsuite, sensei to hanasu tsumori desu.
Tomorrow I intend to discuss this problem with my teacher [instructor, doctor, lawyer, etc.].
*4. Indicates a change or result (commonly used in the phrase to naru)
Orinpikku no kaikai-shiki no hi to natta.
The day of the opening ceremony of the Olympics arrived. (Lit., It became the day of the opening ceremony of the Olympics.)
Kotoshi no kaigai-ryokōsha wa, issen-man-nin to natta.
[The number of] overseas travelers this year reached ten million.
*5. Following an expression of quantity, reinforces the negative idea of the sentence: “(not) as much as.”
Ano yama ni noboru ni wa, ni-jikan to kakarimasen.
It won’t take as long as [won’t take even] two hours to climb that mountain.
Ano kaisha to wa nido to torihiki o shitaku nai.
I don’t want to have dealings with that company ever again. (Lit., I don’t want to have dealings with that company two times [because I’ve dealt with them once already and know what they’re like].)
II. Used after onomatopoeic adverbs, or follows a word, clause, or sentence and precedes such verbs, as iu, kiku, and omou to indicate what someone said, asked, thought, etc.
1. Indicates what someone said, ordered, asked, etc.
Yamamoto-san ga, ato de denwa suru to osshaimashita.
Yamamoto said that she would phone later.
Haha ga sensei ni yoroshiku to mōshite orimashita.
Mother said to give her regards to you (who are my teacher, doctor, etc.).
Watanabe-san ga kuji made ni jimu-sho ni kuru yō ni, to itte imashita.
Watanabe said that you should come to his office by nine o’clock. / Watanabe asked that you come to the office by nine o’clock.
2. Indicates what someone thinks or feels.
Rainen wa, Amerika e ikō to kangaete imasu.
I’m thinking of going to the United States next year.
Densha wa kuji ni deru to omoimashita ga, jūji deshita.
I thought the train would leave at nine o’clock, but [it left at] ten. / Or, I thought the train was going to leave [was scheduled to leave] at nine o’clock, but it turned out to be ten.
3. Indicates the name of something, about which an explanation follows; usually used when the name alone would not be under-stood. Always used in the form to iu (or some variation): “that (who, which) is called, known as.”
“Sekai’ to iu zasshi o shitte imasu ka.
Do you know the magazine Sekai?
Burii Sukaizu to iu hoteru ni tomarimashita.
I stayed at a hotel called Blue Skies.
Mazu, Tanaka to iu buchō ni shorui o moratte kudasai.
First of all, get the documents from a section manager named Tanaka.
4. Used after onomatopoeic adverbs.
Ogawa ga sarasara to, michi no soba o nagarete ita.
A sparkling brook flowed alongside the road.
Hoshi ga kirakira to kagayaite imasu.
The stars are twinkling.
III. Follows verbs and adjectives to form a conditional: “if, unless, whether or not.”
1. Indicates that a second action follows immediately upon the action preceding it; often used with sugu (immediately, right away): “as soon as.”
Note: -Tara (#35, no. 5) and nari (#46, no. 3) can be used here with much the same meaning.
Asa okiru to sugu, kāten o akemasu.
As soon as I get up in the morning, I open the curtains.
Kinō wa kaisha no shigoto ga owaru to, massugu ie ni kaetta.
Yesterday, as soon as work was over, I went home. / I went straight home after work yesterday.
2. Indicates the inevitability of a second action following the one preceding it: “when, as.”
Nihon de wa haru ni naru to sakura ga sakimasu.
When spring comes in Japan, the cherry trees bloom. / In Japan, the cherry trees bloom with the coming of spring.
Kuruma ga ōku naru to kōtsū-jiko ga fuemasu.
As (the number of) cars increases, the (incidence of) traffic accidents rises. / The more cars there are, the more traffic accidents occur.
Fu-keiki ni naru to shitsugyō-sha ga fuemasu.
When there is a recession, the number of jobless increases.
3. Indicates a hypothetical condition: “if, unless.”
Note: -Ba (#34, no. 1) and -tara (#35, no. 1) have much the same meaning. Compare also -ba (#34, no. 2).
Yamada-san ga konai to kaigi ga hajimeraremasen.
If Yamada doesn’t come, the meeting can’t be started. / We can’t start the meeting unless Yamada comes.
Ashita, tenki ga ii to yakyū ga dekimasu.
If the weather is good tomorrow, we can play baseball.
4. Indicates that something has been learned as a result of a certain action: “when, after, as a result of.”
Note: -Tara (#35, no. 4) can also be used with this meaning.
Ginkō e iku to, mō shimatte ita.
When I went to the bank, [I found] it was already closed.
Kōban de michi o kiku to, sono kaisha wa sugu mitsukatta.
After asking the way at a police box, I found [located] the company right away.
5. Used with two verbs (either two different verbs ending in -yo/-o, or the same verb repeated, the first ending in -yo/-o, the second in the negative -mai); indicates a lack of concern over which of the two events occurs: “whether … or (not).”
“En” ga tsuyoku narō to yowaku narō to, watashi no seikatsu ni wa kankei arimasen.
Whether the yen gets stronger or grows weaker [rises or falls], it has no effect on my [daily] life.
Kanojo ga hitori de pati ni ikō to iku mai to, watashi wa kamaimasen.
I don’t care whether she goes to the party alone or not.