A guide to Japanese Grammar: 2

In Japanese by Jeremy Arns

In the first lesson, we learned how to say “Is” and “Is not”. Now let’s learn how to say “Was” and “Was not”, along with some new verbs, adjectives, and how to conjugate them!

You can view the first lesson via this link.

Past and present tense

Before we learn more verbs other than です, let’s learn how to conjugate です (is / am / are) into it’s past tense form (was / were).

でした (polite form)
・だった (plain form)

Using でした or だった makes the sentence past tense, versus ですor which is present tense.

Present tense to past tense (polite): ですでした
Present tense to past tense (plain): だった

Was a forest.

Was a forest.

Simple! This works when you are using a noun (like 森 for “forest”), however if you’re using an adjective or another verb, you wouldn’t be able to use でした or だった to indicate past tense– there are other ways to do that which we’ll get into shortly.

“To do”, “To exist“, and the て form

Let’s learn one of the most common verbs, する, which means “to do”. By conjugating this into different forms, you can say “doing”, “did”, “was doing”, “did not do”, “will not do”, etc!

します (polite form)
する (plain form)

(I) study.

(I) study.

Using します or する indicates that it is an action that you do. Maybe not right this second, but it’s something you do, or will do. If you want to say you’re currently doing something, you’ll want to use the て form, plus another verb– いる (verb used to indicate continuing action, or “to exist”).

First let’s learn how to conjugate する into it’s て form. This logic will work with any verb conjugated into it’s ~ます polite form.


The way you can conjugate a verb into it’s て form is by turning the plain verb into it’s polite ます form. In this case する becomes します. Then, you drop the ます, which just leaves し, and you add て– so it becomes して. Once it’s in the て form, you can add the verb いる to give it tense.

しています (currently doing, polite form)
している (currently doing, plain form)

Let’s see いる in it’s past tense form.

いました (polite past tense)
いた (plain past tense)

As you might have noticed, conjugating verbs into their past tense form follows a pattern. です→でした。います→いました。します→しました。

(I’m) currently studying.

(I’m) currently studying.

(I) was studying.

(I was studying).

(I) studied

(I) studied.

Negative tense (present and past)

Let’s review how to use です in it’s negative present tense form.

です→ではありません (polite form)
だ→ではない (plain form)

Is not a cat.

Is not a cat.

What about how to say “Was not a cat”? This would be in a negative past tense form. To do this, you can simply add でした to the end of the polite negative form: ではありませんでした

Was not a cat.

To do this in the plain form, you take ない, drop the い, and add かった.


Was not a cat.

Adjectives (present and past)

As mentioned earlier (lesson 1), there are different types of adjectives in Japanese– い adjectives, and な adjectives. Let’s start with い adjectives.

楽しい (fun)
甘い (sweet)
美味しい (delicious)

Notice how all of these adjectives end in い — this is because they are い adjectives. Let’s see how these are used in the present tense.

Is fun.

Is sweet.

Is delicious.

Pretty simple! You simply add です to the end of the adjective to say it is that adjective.

This game is fun.

Cake is sweet.

Sushi is delicious.

い adjective negative tense (present)

If you’re a pattern searcher, you might be thinking that the way to say something isn’t that adjective, is to use ではりません instead of です — for instance 楽しいではりません. This is incorrect though, the grammatical way to do this is different than just using ではりません instead of です.

To conjugate an い adjective into it’s negative form, first you must drop the い, add く, and then add ありません (or ない in the plain form).

楽しありません =
Isn’t fun.

楽しない =
Isn’t fun.

Let’s try this out with a different adjective.

This cake isn’t sweet.

Not too difficult! Just drop the い, add く, and then use ない or ありません.

Let’s do this in the past tense and polite form. To do this, simply add でした to the end of the stem.

Was not fun.

い adjective past tense

い adjectives in it’s past tense conjugates the same way in both the polite form and plain form– the only difference is that in the polite form you add です to the end. This might seem confusing because です is in the present tense, however when the adjective is conjugated in it’s past tense, the sentence is still past tense. (If you think about it, if something was, it’s still in that same state of was).

To conjugate an い adjective to past tense, simply drop the い, and add かった

Was fun.

And in it’s polite form, you simply add です, like this:

Was fun.

This works the same way for if you want to say something “Wasn’t fun”:

Wasn’t fun.

Wasn’t fun.

That’s all for now. Stay tuned for the next lesson!

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