something that is very easy to do
что-то очень легкое сделать (chto-to ochen legkoe sdelat)
"The exam was a piece of cake for me."
"Экзамен был проще простого для меня." (ekzamen byl proshe prostovo dlya menya)
to make maximum effort even when it’s tough
to take responsibility for what you did wrong.
to refresh one’s mind or body after inactivity
to be fully understood or have a strong impact
it's not difficult to understand
to make someone take responsibility for their actions