Base 3 + koto ga dekimasu
Koto ga dekimasu is a long one, and is added to the plain (Base 3) form of a verb to simply show ability to do that verb. But first, in order to make this lesson as uncomplicated as possible, let's look at each part.
First is koto. No, this isn't the well-known instrument of Japanese classical music. This is the mundane koto that gets lots of daily wear and tear changing Japanese verbs to nouns. Well, it really doesn't change the verb, it is added after the verb so that it can be used like a noun. In English, we add ing to make a noun out of a verb, like reading in the sentence I like reading. (Remember studying "gerunds" in school?) Anyway, in Japanese we do the same thing by adding koto after a plain verb form. Like our ing, koto has no practical use by itself. If you have to have a translation, "the thing of" is probably the closest you can get. Better than all this talk would be an example. Watch carefully:
yomu (to read) + koto (the thing of) = yomu koto (the thing of reading; reading as a noun [gerund])The literal translation of the above example would be "I like the thing of reading; I like reading as a thing to do." Does this help? If not, no problem. It'll come. Let's move on.
Next, the verb dekiru means "can" or "be able to." In this lesson it is shown in its polite form dekimasu, but dekiru is also fine when you don't need to be polite. (If you need to review ichidan verbs with masu go back to Lesson 3.)
Finally, the particle ga is what you use to join koto and dekimasu. Just think of koto ga dekimasu as a set phrase. Here are some examples:
"Bob wa Junko ni denwa suru koto ga dekimashita."can be shortened to:
"Bob wa Junko ni denwa dekimashita."Denwa is a noun, and adding the suru makes it a verb, so instead of adding koto to make it a noun again (and long one), you can just omit suru. Here are a couple more:
Again, dekiru or one of its forms can directly follow a noun as long as it's one that uses suru to change it to a verb; in that case the suru is omitted. After verbs you add koto ga before dekiru.
There is a short alternative for other verbs, but that'll have to wait until we get into the Base 4 endings.
One last thing: I described the meaning of koto as "the thing of," but please don't think that koto can mean any "thing." It generally means intangible "things": ideas, essences, meanings, expressions, actions, etc. It means "thing" as used in the sentence saving money is a good thing. It is generally not used for physical things or objects. It does not mean "thing" in money is a good thing to have. There is another word in Japanese which is used for physical things: mono; but we'll have to save that one for a future lesson.
Matsu koto ga dekimasu ka. (Can you wait?)
koto: the "thing" or idea of something done
(Verbs are shown in their plain form.)