Giving an opinion with reasons in Japanese: と思います and なぜなら…からです

Level B1

Giving an opinion with reasons in Japanese: と思います and なぜなら…からです

By the end of this lesson you can answer a familiar question, such as where it's better to study, and defend your choice. The central idea is this: say what you think with と思います (to omoimasu), then back it up in a new sentence with なぜなら (naze nara) … からです (kara desu), add a second short reason with それに (sore ni) and show one concrete case with 例えば (tatoeba). Before からです the plain form is used, just as it is before と (to).

Warm-up: comparing, opinions, reasons

These pieces come back in this lesson, even if this is the first time you see them. お茶よりコーヒーのほうが好きです (ocha yori kōhī no hō ga suki desu), “I like coffee more than tea”, compares two options: より (yori) marks the reference and のほうが (no hō ga) the one that has more of that quality. 公園は大きいと思います (kōen wa ōkii to omoimasu), “I think the park is big”, gives an opinion, with the plain form before と. That's why a noun takes だ (da) there: それは本だと思います (sore wa hon da to omoimasu), “I think that's a book”. どうしてですか (dōshite desu ka) asks “Why is that?”. ここはきれいですから、ここで食べましょう (koko wa kirei desu kara, koko de tabemashō), “It's clean here, so let's eat here”, puts the reason first and closes it with から. This lesson also lets you put the reason second.

Three words for an argument, and the words of our question

なぜなら (naze nara) opens a sentence that gives a reason. それに (sore ni) adds one more point. 例えば (tatoeba) introduces a concrete case. The other six words belong to the question this lesson discusses: 図書館 (toshokan, library), 勉強 (benkyō, studying), 静か (shizuka, quiet), うるさい (urusai, noisy), 便利 (benri, convenient) and おいしい (oishii, tasty). The list shows 静かな, the form used before a noun, and the kanji spelling 美味しい; the sentences here use 静か and おいしい. 静か and 便利 work like きれい, and うるさい and おいしい work like 大きい (ōkii, big). That difference matters in a moment.

Model: the library or a café?

Listen once without reading. Two people who barely know each other talk politely about where to study. 勉強は (benkyō wa) at the start sets the topic, “as for studying”, and どちらがいいと思いますか (dochira ga ii to omoimasu ka) joins the comparison question to と思います. どちら (dochira) is “which of the two”. That sentence has two と: 図書館とカフェ links the two options, and と思います marks what you think. カフェ (kafe) is “café”, and 本 (hon) is “book”. B answers in one go: opinion, reason, second reason. 土曜日 (doyōbi) is “Saturday”, 人 (hito) is “person” and たくさん (takusan) is “a lot”. そうですか (sō desu ka) means “I see”, and でも (demo) is “but”. A then gives the reason with からです alone: in conversation, when the reason comes straight after your own opinion, なぜなら can be left out. それもいいと思います (sore mo ii to omoimasu), “I think that's good too”, closes the talk kindly: nobody has to win.

Your opinion: …と思います

Put your opinion before と思います, in the plain form. Words like いい (ii, good) and うるさい stand alone, while words like 便利 and 静か take だ: 便利だと思います (benri da to omoimasu). Comparing works as you know it: 図書館のほうがいいと思います (toshokan no hō ga ii to omoimasu), or 図書館はカフェより静かだと思います (toshokan wa kafe yori shizuka da to omoimasu), “the library is quieter than a café”.

私は (watashi wa) at the start sets your view apart from someone else's. You can leave it out, as most examples here do. と思います marks a sentence as your opinion rather than a stated fact, and speakers use it even when they feel sure, so it doesn't sound as hesitant as “I think” can. To ask, use the last two examples: with two options, どちらがいいと思いますか; about one thing, 図書館をどう思いますか (toshokan o dō omoimasu ka), with を (o) and どう (dō, how). どう takes the place of the opinion, so there's no と here: you don't say どうと思いますか.

図書館のほうが／カフェはいい／うるさい／便利だと思います

The reason: なぜなら…からです

なぜなら opens a new sentence that gives the reason for what you've just said, and からです closes it, so the two frame the reason. なぜなら doesn't replace から: the sentence still ends in からです. English “because” can sit in the middle of one sentence, but in this lesson なぜなら always starts a sentence of its own.

Inside the frame, the plain form goes before から, as it does before と. Words like おいしい stand alone: おいしいからです. A verb is in its plain form: ある (aru), “there is”, gives あるからです. Words like 静か and nouns take だ: 静かだからです, テストだからです. So 静かからです and おいしいだからです are wrong. In the last example, 今日 (kyō) is “today”, 明日 (ashita) “tomorrow”, テスト (tesuto) “test”, で (de) marks where you study, and 勉強します (benkyō shimasu) is “study”.

なぜなら、静かだ／本がたくさんある／コーヒーがおいしい／明日はテストだからです

Reason first or reason last

The same reason can come in two orders. ここは静かですから、ここで勉強します (koko wa shizuka desu kara, koko de benkyō shimasu) gives the reason first: です stays before から and the sentence goes on to the decision. ここで勉強します。なぜなら、ここは静かだからです gives the decision first, which suits an opinion you want to defend: the plain form comes before から, and です closes the sentence. ここ (koko) is “here”.

When someone asks どうしてですか, you normally skip なぜなら and answer 静かだからです (shizuka da kara desu), or 静かですから as you already know it. なぜなら is for offering a reason yourself, and it sounds careful, so it suits a discussion, a presentation or writing. Among friends you'll hear something like the last line, with plain forms and no なぜなら; here you only need to recognize it.

A second reason: それに

Two short reasons are enough to defend a preference. Give the first with なぜなら…からです. Then start a new sentence with それに, “besides”, and close it with からです too. Don't repeat なぜなら. Japanese has other ways to link points, but this lesson needs only this one.

なぜなら、静かだ／コーヒーがおいしいからです。それに、本がたくさんある／便利だからです

One concrete case: 例えば

例えば opens a sentence with one concrete case that shows what you've just said. It isn't a reason, so in these examples the sentence ends normally, without からです: なぜなら says why, and 例えば shows a case. English “for example” can come at the end of a sentence, but 例えば can't: it comes before the case it introduces.

There are two verbs for “there is”: います (imasu) for people and animals, あります (arimasu) for things and places. Words in the examples: 高い (takai, expensive), 六百円 (roppyaku en, 600 yen), 駅 (eki, station), 駅の近くに (eki no chikaku ni, near the station), and 日本語の本も (nihongo no hon mo, books in Japanese too), where も (mo) means “too”.

カフェはうるさいと思います／カフェは便利だと思います。例えば、土曜日は人がたくさんいます／駅の近くにあります

Your turn, and the summary

Cover the two answers. Listen to the question, pick the library or the café and defend it aloud: opinion, reason, second reason, example. Then compare with the answers, which use only words from this lesson. Your own reasons are welcome.

In short: と思います gives your opinion; なぜなら…からです gives the reason in a new sentence, with the plain form before から; それに adds a second short reason; 例えば shows one case; and after どうしてですか, からです is enough.

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