What is the difference between ことにする and ことにした?


みんなの日本語 中級I - Lesson 3 says that V (dictionary form) ことにする is used to express
the decision to do something. If I say

> 私は日本へ行くことにしました。

this can be translated as “I decided to go to Japan”. This is perfectly clear
to me. However, what is the correct translation for

> 私は日本へ行くことにします。

? Is it “I will decide to go to Japan”, “I decide to go to Japan”, or “I
decided to go to Japan”? Can you explain to me when to use する in non-past
tense?




We don't have a perfect parallel structure in English. The deciding is not in
the future tense even though the action that follows is.

I would go with:

> I will go to Japan.

At least for me, the most common type of the present tense にする that I hear is
for ordering food.

> らーめんにします。

=

> I will have the ramen.

In both cases, I take _will_ not to be the future tense but the volitional
will. You could replace with _choose_




We don't have a perfect parallel structure in English. The deciding is not in
the future tense even though the action that follows is.

I would go with:

> I will go to Japan.

At least for me, the most common type of the present tense にする that I hear is
for ordering food.

> らーめんにします。

=

> I will have the ramen.

In both cases, I take _will_ not to be the future tense but the volitional
will. You could replace with _choose_

