Page 242 - English Grammar in Use

Unit
115 unless as long as provided

A unless
Study this example situation:

The club is for members only.
You can’t go in unless you are a member.

This means:
You can’t go in except if you are a member.
You can go in only if you are a member.
unless = except if

Some more examples of unless:
I’ll see you tomorrow unless I have to work late.
(= except if I have to work late)
There are no buses to the beach. Unless you have a car, it’s difficult to get there.
(= except if you have a car)
a: Shall I tell Lisa what happened?
B: Not unless she asks you. (= tell her only if she asks you)
Ben hates to complain. He wouldn’t complain about something unless it was really bad.
(= except if it was really bad)
We can take a taxi to the restaurant – unless you’d prefer to walk. (= except if you’d
prefer to walk)
Instead of unless it is often possible to say if … not:
Unless we leave now, we’ll be late. or If we don’t leave now, we’ll …

B as long as / so long as and provided / providing
You can say as long as or so long as (= if, on condition that):
⎧ as long as ⎫
You can borrow my car ⎨ ⎬ you promise not to drive too fast.
⎩ so long as ⎭
(= You can borrow my car, but you must promise not to drive too fast. This is a condition.)
You can also say provided (that) or providing (that):
⎧ provided (that) ⎫
Travelling by car is convenient ⎨ ⎬ you have somewhere to park.
⎩ providing (that)⎭
(= It’s convenient but only if you have somewhere to park.)
⎧ Providing (that) ⎫
⎨ ⎬ the room is clean, I don’t mind which hotel we stay at.
⎩ Provided (that) ⎭
(= The room must be clean, but otherwise I don’t mind.)

C unless / as long as etc. for the future
When we are talking about the future, we do not use will after unless / as long as / so long as /
provided / providing. We use a present tense (see Unit 25):
I’m not going out unless it stops raining. (not unless it will stop)
Providing the weather is good, we’re going to have a picnic tomorrow.
(not providing the weather will be good)

230 if ➜ Units 25, 38–40