JLPT N2
ことだ
should do ~ (used for suggestions or giving advice)
Structure / Usage
Verb (dictionary form / ない form) + ことだ
Example Sentences
健康のために、早く寝ることだ。
For your health, you should go to bed early.
試験に受かりたければ、毎日勉強することだ。
If you want to pass the exam, you should study every day.