你需要戴安全帽。你需要戴頭盔。

You need to wear a helmet.

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 需要 xūyào
  1. to need; to want; to demand; to require
  2. needs
=3 戴 Dài surname Dai
=3 戴 dài
  1. to put on or wear (glasses, hat, gloves etc)
  2. to respect
  3. to bear
  4. to support
4 安全帽 ānquánmào safety helmet; hard hat

classifier: 頂
=5 你 nǐ you (informal, as opposed to courteous 您 nín)
=5 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.)
6 需要 xūyào
  1. to need; to want; to demand; to require
  2. needs
=7 戴 Dài surname Dai
=7 戴 dài
  1. to put on or wear (glasses, hat, gloves etc)
  2. to respect
  3. to bear
  4. to support
8 頭盔 tóukuī helmet