Overview

These linkers replace or refine if in conditional sentences. They work with the usual tense choices (present → will/can/may, past simple → would, past perfect → would have, etc.). Choice of linker adds nuance: exception, precaution, strong requirement, or certainty regardless of the condition.

unless (= “if … not”)

• I won’t go on holiday unless I save some money. (= if I don’t save)
• Use an affirmative clause after unless; avoid double negatives: ✗ unless I don’t… → ✓ unless I…
• Not … unless = “only if”: You can’t enter unless you show ID.
• Unless works with imperatives: Don’t call me unless it’s urgent.

Unless often expresses an exception; if … not is neutral. With many speakers, unless sounds more formal in writing.

in case (precaution)

• Action is done to be prepared for a possible situation: I’ll take an umbrella in case it rains.
• Past narrative: We took snacks in case we got hungry.
• Not the same as if for results: If it rains, I’ll call you (=result). I’ll call you in case it rains means “so you’re prepared”.
• just in case (informal intensifier): Bring cash, just in case.
• in case of + noun: In case of fire, use the stairs.

Strong conditions: as long as, so long as, provided/providing (that), only if, on condition (that)

All emphasise a requirement. Register varies: as/so long as (neutral), provided/providing (slightly formal), on condition (that) (formal/legal), only if (strong focus).

• I’ll tell you the whole story as long as you keep it secret.
• We’ll lend you the equipment provided (that) you return it by Friday.
• They will speak to the press on condition (that) their names are withheld.
• We’ll invest only if you can show proof of funding.

Inversion with sentence-initial “only if”: when the “only if” clause comes first, invert the subject and auxiliary in the main clause: Only if you agree will we proceed.

whether or not / even if

• whether or not: the result is the same in both alternatives: I’ll help him whether or not he needs me.
• even if: emphasises that the result holds despite a (often unlikely) condition: Even if you apologise, he won’t forgive you.
• Both can be mid or initial position; comma is optional and style-based when initial.

suppose/supposing/what if

• Imagine a situation and consider consequences.
• Real possibilities → present + future: Suppose she calls, what will you say?
• Unreal/remote → past simple/ perfect + would: What if you lost everything? / Supposing you hadn’t told me, I’d have behaved differently.

Form & punctuation quick tips

• When the conditional clause comes first, a comma is usual: Provided that you agree, we’ll start.
• Keep the tense logic of standard conditionals (zero/first/second/third) even with alternative linkers.
• Modal variety in the result: may/might/can/could/should show degree of certainty or permission.

Mini reference

Nearby connectors that express results rather than conditions: otherwise / or else (e.g., Leave now, otherwise you’ll be late.).