GUIDE ENGLISH GRAMMAR BOOK

32 CONDITIONAL CLAUSES
PAGE 340
6 Unless
a Unless means 'if... not'.
We're going to have a picnic unless it rains/if it doesn't rain.
You can renew a book unless another reader has requested it.
Unless you refund my money, I shall take legal action.
NOTE
We can use not unless meaning 'only if'.
We won't have a picnic unless it's fine.
Aren't you going to join us?~ Not unless you apologize first.
b
When an unreal condition comes before the main clause, we cannot use unless.
The horse fell. If it hadn't fallen, it would have won the race.
NOT Unless it had fallen, it would have won.
But we can use unless after the main clause, as an afterthought.
The horse won easily. No one could have overtaken it, unless it had fallen.
We do not use unless when we talk about a feeling which would result from
something not happening.
Alex wlll be upset if you don't come to the party.
I shall be very surprised if it doesn't rain.
NOTE
The adverb otherwise means 'if not'.
You are obliged to refund my money. Otherwise I shall take legal action.
c
We can use and and or to express a condition, especially in informal speech.
Touch me and I'll scream. (= If you touch me, I'll scream.)
Go away or I'll scream. (= Unless you go away, I'll scream.)
7 In case
You should insure your belongings in case they get stolen.
(= ... because they might get stolen.)
I took three novels on holiday in case I felt like doing some reading.
We can use should.
Take a pill in case the crossing is rough/should be rough.
Compare if and in case.
I'll draw some money out of the bank if I need it.
(= I'll draw it out at the time when I need it.)
I'll draw some money out of the bank in case I need it.
(= I'll draw it out because I might need it later.)
But for in case of, • (4) Note c.
NOTE For in case in American English, • 307(2).
8 Even if and whether ...or
I wouldn't go on a camping holiday, even if you paid me.
NOT I wouldn't go even you paid me.
Joanne wouldn't want a dog even if she had room to keep one.
She wouldn't want a dog whether she had room for one or not.
Whether it's summer or winter, our neighbour always wears a pullover.