Making Appointments with Friends

If you want to say "something must be done," these two phrases are quite useful.

なければ [nakereba]

• This is the conditional form of ない [nai] (the negative form of a verb).
• It literally means "if (something) does not happen."

なりません [narimasen]

• This comes from なる [naru] ("to become") and ません [masen] (polite negative form).
• In this context, it means "cannot become" or "it won't do."

勉強しなければなりません [benkyō shinakereba narimasen]
I must study.

• 勉強しなければ [benkyō shinakereba] means "If I don't study,"
• なりません [narimasen] means "it won't do."

掃除しなければなりません [sōji shinakereba narimasen]
I must clean it.

• 掃除しなければ [sōji shinakereba] means "If I don't clean,"

• A: もうちょっとだったのに！
  I was so close!
• A: もう一回しましょうか？
  Shall we try do it one more time?
• B: 勉強しなければなりません [benkyō shinakereba narimasen]
  We have to study.
• A: 勉強して、ゲームをしましょうか？
  Shall we study and then play games?
• B: 掃除しなければなりません [sōji shinakereba narimasen]
  We have to clean.
• A: はーい…
  Okay..