Auxiliary verb

Also known as "modal verbs"

Express capability, possibility, necessity, obligation or willingness.

Notes

  • Can indicate intention, possibility or necessity
    • Differing strength levels within these categories (e.g. 必须 vs 应该)
    • Modal verbs of strong obligation (必须, 比得) can't form positive-negative questions
  • In sentences with an auxiliary verb, the auxiliary verb is negated, not the main verb.
  • To respond to questions with an auxiliary verb, the auxiliary verb is used, not the main verb. E.g. 你想不想来? 想.
  • Auxiliary verbs can't be reduplicated.
  • Aspect particles 了, 着, 过 can't be used with auxiliary verbs.
  • Auxiliary verbs must take a verb as an object, not a noun.
  • Most important auxiliary verbs:
    • 应该
    • 必须
    • 得 (děi)
  • How to say 'can' in different contexts (Hui, neng, and keyi|会, 能, and 可以)

Sources and further reading