If you are anything like me, then you love to give people advice. I can’t always attest that I give the best advice, but I like to give it nonetheless.

In Japanese there are a few great ways to tell people they should or should not be doing something. In this lesson I want to go over one of them: ことだ or more formally, ことです.

ことだ is used at the end of a sentence and has the general meaning of “should.” It is a stronger expression than ～方がいい (～ほうがいい), which you have probably learned before.

In fact, ことだ is mostly used when you are speaking to someone who is lower than you on a social level. It comes off a bit like you are giving some parental advice or stating a soft rule that someone should follow. Because of this, you would never use ことだ with your boss, or when giving advice to people of higher status than yourself.

Depending on whether the verb is positive or negative, ことだ can roughly correspond to "should" or "shouldn't," respectively.

So here are the verbs we'll use in this lesson:

触れる（ふれる // to touch; to feel; to experience）
泣く（なく // to cry）
ためる（to accumulate; to amass）
貸す（かす // to lend）

Here is the construction:

Vる + ことだ（should V）
触れることだ（ふれることだ // should touch; should experience）
泣くことだ（なくことだ // should cry）

Vない + ことだ（shouldn't V）
ためないことだ（ためないことだ // shouldn't accumulate）
貸さないことだ（かさないことだ // shouldn't lend）

Note that either ことだ or ことです is OK depending on the formality of the sentence.

Look at the sentences below and try to think of who might be speaking to whom. When you can imagine a situation with an example sentence, it is much more likely to stick in your head.

日本語の上達のためには、とにかく日本語に触れることだ。
にほんご　の　じょうたつ　の　ために　は、　とにかく　にほんご　に　ふれる　ことだ。
In order for your Japanese to improve, you should get exposure to Japanese.
Literally: “Japanese + の + improve + の + ため + は + in any case + Japanese + に + touch / experience + ことだ.”

悲しいときは、我慢しないで思い切り泣くことだ。
かなしい　とき　は、　がまん　しないで　おもいきり　なく　ことだ。
When you are sad, don’t hold back. You should cry to your heart's content.
Literally: “sad + when / time + は, + patience + don't do (and) + to your heart's content + cry + ことだ.”

病気になりたくなければ、まずはストレスをためないことです。
びょうき　に　なりたくなければ、　まず　は　ストレス　を　ためない　ことです。
If you don’t want to become sick, firstly, you shouldn’t let stress build up.
Literally: “sick + に + if don’t want to become, + first + は + stress + を + don’t accumulate + ことです.”

お金の貸し借りはトラブルのもとです。友達にいくら頼まれても貸さないことです。
おかね　の　かしかり　は　トラブル　の　もと　です。　ともだち　に　いくら　たのまれても、　かさないことです。
Borrowing and lending money leads to trouble. No matter how much they ask for, you shouldn't lend money to friends.
Literally: “money + の + borrowing and lending + は + trouble + の + source + です .+ friends + に + how much + even if requested + don’t lend + ことです.”

Think about people lower than you in social status. Your employees, younger siblings, children, or even students. Can you think of a few ways you might give them some advice using ことだ?

Now try the other way, think of people that are higher than you in social status. Maybe your boss, or a higher level employee, your parents, a police officer, or a doctor you are seeing. Can you think of ways they might give you advice or tell you not to do something using ことだ? Write at least 4 sentences using this grammar point.

And while we are giving advice, I think you should find a dog to pet. Its homework. (If you are allergic, I apologize for making you sneeze while doing homework…)

This lesson was written by Cassy L., a guest contributor: