Japanese Verb Rules - Potential Form

Potential form

This verb form expresses a certain ability of the Topic or the possibility of an event.

How to derive the Potential form:

Group 1: Change the final る to られる
Group 2: Change the final vowel u to e and add る
Group 3: くる→こられる、する→できる

できる is really not the potential form of the verb する. できる is an individual verb. Since できる already exists, it can be used as the potential form of the verb する.

How to use the form:

The following sentence is an example in which an ability of the Topic is expressed. The Direct Object should be marked by が instead of を in this construction.

	がくせい		かん	じ		か
あの	学生	は	漢	字	が	書	けます。

'That student can write Kanji.'

The following example indicates that the form may be used to express the possibility of an event.

	とうきょう		い
あのバスで	東京	に	行	けます。

'You can go to Tokyo by that bus.'

Some verbs that refer to a condition or event that a person has no control over lack the potential forms （ある ("possess"), 分かる（わかる "understand"）, 雨が降る（あめがふる "rain"）, 下さる（くださる）、いる（"need"））.