JAPANESE VERB

くさる

腐る

to go off, to rot

Conjugation

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Form	Polite	Plain
AffirmativeI go off
NegativeI don’t go off

finished actions

Form	Polite	Plain
AffirmativeI went off
NegativeI didn’t go off

て形 · joining actions, “doing”, requests

可能形 · “can”

Form	Polite	Plain
AffirmativeI can go off
NegativeI can’t go off

たい形 · “want to”

Form	Polite	Plain
AffirmativeI want to go off
NegativeI don’t want to go off

意向形 · “let’s”, “I’ll”

Form	Polite	Plain
Let’slet’s go off

条件形 · “if” and “when”

命令形 · from gentle to blunt

受身形・使役形 · “is done”, “make someone do”

Form	Polite	Plain
PassiveI am gone off
CausativeI make someone go off

One sentence for each tense, the way people say it.

Present and future

なつはたべものがすぐ くさります。

In summer food goes off quickly.
Past

ふくろのなかのバナナが くさった。

The bananas in the bag went off.
Te-form

このさかな、 くさって いるとおもう。

I think this fish has gone off.
Potential

くさる まえに、ぜんぶたべきれません。

I can't eat it all before it goes off.
Want to

やさいをくさらせたくないから、すぐつかいます。

I don't want the vegetables to go off, so I use them right away.
Volitional

くさる まえに、りんごでジャムをつくろう。

Before they go off, let's make jam with the apples.
Conditional

にくは くさったら、においでわかります。

If meat has gone off, you can tell by the smell.
Commands and requests

くさりやすいから、そとにおかないでください。

It goes off easily, so please don't leave it out.
Passive and causative

くさった たまごはすぐすてられた。

The rotten egg got thrown out right away.

くさる is for food that goes bad; くさっている means it is already off.
Food goes off by itself, so the potential, want, volitional, imperative and passive sentences show くさる beside another verb.

The same pattern, on other verbs: godan verb (u-verb).