(i) plunge in –go straight to the topic

Yes, but we need research before we plunge in - this isn't simple stuff.

(ii) kept back – stay indoors

Students who fail the exam may be kept back a year.

(iii )move up –go to the next grade

The result will determine whether they will move up to fourth grade.

(iv) ramble on –speak or write without focus

Do not let your answers ramble on too long.

(v) get along with –have a good relationship with

He is sincere and easy to get along with.

(vi) calm down –make (them) remain quiet

The mayor asked the protesters to calm down so he could speak.

(vii) stay in – not promoted

Let's stay in tonight and watch a movie.

(viii) make up for – compensate

I worked extra hours to make up for the time I had missed.

(ix) hand in – give an assignment (homework) to a person in authority (the teacher)

I hand in my homework to Ms. Keemly.