Ability and potential can be expressed by two different ways.

(1) Attaching the phrase "~ koto ga dekiru （～ことができる）" after the basic form of the verb. Literally "koto （こと）" means "thing," and "dekiru （できる）" means "can do." The formal form of "~ koto ga dekiru （～ことができる）" is "~ koto ga dekimasu （～ことができます）," and past tense is "~ koto ga dekita (~ koto ga dekimashita)."

"~ dekiru （～できる）" can be directly attached to a noun, if a verb is closely associated with its direct object.

(2) By potential form of the verb. Potential verb forms are formed as shown below.

In informal conversation, "~ra （～ら）" is often dropped from potential form of RU-verbs. For example, "mireru （見れる）" and "tabereru （食べれる）" instead of "mirareru （見られる）" and "taberareru （食べられる）."

The potential form of the verb can be replaced with the form using "~ koto ga dekiru （～ことができる）." It is more colloquial and less formal to use the potential form of the verb.

Here are some exercises. Translate into Japanese.

(1) I can write hiragana.
(2) I can't drive a car.
(3) Can you play guitar?
(4) Tom could read this book when he was five.
(5) Can I buy the ticket here?

Here are the answers to the exercises.