YOU SAID:

I need to get some milk

INTO JAPANESE

私はミルクを取る必要がある

BACK INTO ENGLISH

Should I take the milk.

INTO JAPANESE

ミルクを取る必要があります。

BACK INTO ENGLISH

You must take the milk.

INTO JAPANESE

牛乳を取る必要があります。

BACK INTO ENGLISH

You must take the milk.