你该剪头发了。

You should get your hair cut.

Source: Tatoeba

Sentence Composition

=1 你 nǐ you (informal, as opposed to courteous 您 nín)
=1 你 nǐ you (Note: In Taiwan, 妳 is used to address females, but in mainland China, it is not commonly used. Instead, 你 is used to address both males and females.)
2 该 gāi
  1. should
  2. ought to
  3. probably
  4. must be
  5. to deserve
  6. to owe
  7. to be sb's turn to do sth
  8. that
  9. the above-mentioned
3 剪头发 jiǎntóufa (to get a) haircut
=4 了 le
  1. (completed action marker)
  2. (modal particle indicating change of state, situation now)
  3. (modal particle intensifying preceding clause)
=4 了 liǎo
  1. to finish
  2. (used with 得 dé or 不 bù after a verb to express (im)possibility, as in 忘不了 wàngbuliǎo "cannot forget")
  3. (literary) (usually followed by a negative such as 無 wú or 不 bù) completely (not); entirely (not); (not) in the least
  4. to understand clearly (variant of 瞭 liǎo)
=4 了 liǎo
  1. (of eyes) bright
  2. clear-sighted
  3. to understand clearly
=4 了 liào unofficial variant of 瞭 liào