しか〜ない

About

Pair the particle しか with a negative verb (commonly simply 「ない」) to express that there is "only X" of something. Usually, しか～ない implies that the speaker thinks the current amount is not sufficient.

The following patterns are possible:

～しかない
E.g. ピザしかない。
"There's only pizza."

しか～ない
E.g. ピザしか食たべない。
"(They) only eat pizza."

The ない component of しか～ない may be conjugated to indicate tense and politeness.

Summary

• 

  しか～ない means "there is only X"

• 

  しか～ない implies the speaker thinks that the amount of something is insufficient