必須 — must, have to. · Tsumugu Grammar

grammar → 必須

TSUMUGU · TBCL 3 (est.) · 語法

必須 grammar point · tier 1 · 必須 — modal of hard necessity (must, have to, no alternative)

Auxiliary before a verb: marks the action as required with no alternative — must, have to.

Hook inherited from 應該.

Auxiliary before a verb

框 · Frame

[subj] 必須 [verb phrase]

觸 · Trigger

You are stating that an action is required and no other course is open.

序 · The move

1name who the requirement falls on: the subjectis this a hard requirement, not merely advisable?

2set 必須 directly before the verb phrasedoes 必須 sit before a verb, not a noun?

3negate the necessity with 不必 or 不用, not 不必須did you mean 'need not' (不必/不用)?

例 · Examples

1這場會議很重要，你必須must / have to (no alternative)準時on time參加attend / take part。

This meeting is important; you have to attend on time.

界 · Boundary

要

必須 is hard necessity — the action cannot be waived (你必須參加). Obligation 要 lays a requirement that still bends toward wish or plan (你要參加). 必須 closes off the alternatives; 要 only weights the action.

應該

必須 says it must happen, no choice (你必須去). 應該 says it ought to happen, the right thing to do but still declinable (你應該去). 必須 removes the option; 應該 recommends keeping it.

negating with 不必須: 你不必須參加 → 你不必參加 / 你不用參加（不必/不用 = need not）

putting a noun after 必須: 你必須這個會議 → 你必須參加這個會議（必須 + verb）

softening 必須 where only advice is meant: 你必須多休息（you have no choice but to rest）→ 你應該多休息（you ought to rest）

English 'must' and 'have to' cover both hard necessity and ordinary obligation, so learners reach for 必須 where 要 or 應該 fits, overstating a soft duty as a non-negotiable one. Its negation also splits: 'don't have to' is 不必/不用, never 不必須.