Conditionals: other expressions (unless, should, as long as)


Unless

Conditional clauses can begin with unless. Unless means something similar to ‘if … not’ or ‘except
if’.

The verb forms in the examples are similar to sentences with if: we use the present simple in
the unless-clause and shall, should, will, would, can, could, may or might in the main clause:

Unless I phone you, you can assume the train’s on time. (If I do not phone you /except if I phone
you, you can assume the train is on time.)

Warning:

We don’t use unless for impossible conditions:

If the government had not raised food prices, there would not have been so many protests.

Not: [DEL: Unless the government had raised food prices :DEL]  …

Warning:

We don’t use unless and if together:

We’ll go to the coast tomorrow unless it rains.

Not: [DEL: We’ll go to the coast tomorrow unless if it rains :DEL] .

Should you (Should with inversion)

In formal situations, we can use should + subject (s) + verb (v) instead of if:

Should you wish to cancel your order, please contact our customer service department on 02317
6658932. (or If you should wish to cancel your order …)


Had you (Had with inversion)

In formal situations, we can use had + subject + verb instead of if in third conditional sentences:

Had I known you were waiting outside, I would have invited you to come in. (If I had known you were
waiting outside …)

As long as, so long as, providing, etc.

Sometimes we need to impose specific conditions or set limits on a situation. In these cases,
conditional clauses can begin with phrases such as as long as, so long as, only if, on condition
that, providing (that), provided (that).

As long as is more common in speaking; so long as and on condition that are more formal and more
common in writing:

[to a group of children]

You can play in the living room as long as you don’t make a mess.

So long as a tiger stands still, it is invisible in the jungle.

The bank lent the company 100,000 pounds on condition that they repaid the money within six months.

Providing (that) is more common in speaking; provided (that) is more formal and more common in
written language:

[talking about rail travel in the UK]

You can get a senior citizen’s reduction providing you’ve got a railcard.

They may do whatever they like provided that it is within the law.


Or and otherwise

We often use or and otherwise with conditional meanings:

You’ve got to start studying, or you’ll fail all those exams. (If you don’t start studying, you
will fail the exams.)

[talking about sending a package by mail]

We’d better send it express, otherwise it’ll take days. (If we do not send it express, it will take
days.)


Supposing

Supposing may be used with a conditional meaning. It can be used in first, second or third
conditional sentences. The speaker invites the listener to imagine a situation:

Supposing I don’t arrive till after midnight, will the guest-house still be open?(Imagine if I
don’t arrive till after midnight …)

Supposing you lost your passport, you’d have to go to the embassy, wouldn’t you?

Supposing he hadn’t recognised us – he might never have spoken to us.

In case (of)

They will cancel the concert in case it rains /in case of rain.