conditionals:· true, r,eal and unreal always true (zero conditional) if X happens, Y happens These sentences desc ribe what always happens in «:ertaln c.in:ium tances 1eg sc.ie11t ific fads.

present simple pres.ent simple

When / If you press the, swlt:c/1. rhe fight comes on.

re·al c;onditions (condjtiona:l 1) if X happ1ens, ¥ willl happen

These sentences describe what the speaker thinks wrll posslbly happen as a consequence of a real sitU<il'tio~

p!iesent simple will future

If we do not deal with the g/abal warmir19 problem, temperatures will rise.

If we leave now. we 'II catch rile bus. If we don 'r leave now, we won't c::a tth ir.

In informal speech, we often use going to ins-tead of wllJ.

ff you don't take an umbrella. you ·~ go,irig to get tNi?t We also us e might or can I could in place of will. See Unit 25

We can also u5e ~mperatives in real conditions. rf you don't know i!1 word, look it up 111 t/1~ diUiLJnary.

Sent~nces beginning If you will ... are only used whe.11 will means insist or is 1,11sed as a polite form. If you will stay up so lace. lhen of course you'll feel tired. (insist} ff you'll wait frere, I'll see if the manager 1s ready. (pol1lte}

unless Unles'l means only if not. We u<;e a when we say that if something does not happen, som ething else will happen _

Unless we deal with tile globlll wdfmin9 problem. average Pmperalurf'S will rise.

provided, as Jong as + present simple Pmvided and as long as mean only if.

Provided I as long as we redur.e E"riergy consumpl•OIP, we rari !>fuw tiow11 y/u/ml wamlmg_

in case + 1present simple Thi> desuibes a pOs!>ible situation we want to be prepared for.

Take an umbrella in case it rains ..

unreal conditions {conditional 2} if X happened, Y would happen These sentences describe what the speaker th inks wou l!d happen in an imaginary situation.

pa5tsimple wo,uld +verb

If you wer:e on Venus, you would see the Sun rise l.n the we.n.

Wilat would happen if lhe art/1 stopped !Uming? If aie Earth didn't have a Moon. there wouldn't be any tides.

The past sirnple tense we use in an if-sentence does not describe past t ime, but unreal time. We also use might or C·o.uld In place o:f would. See Unit 25.

if I were you We give advice with If I were you.

I W•oufdn't: do that, if I were you. or If I were you, I wouldn't do that.

_al or unreal? - r s depends on the situation of the speaker, or what the peaker is th inking.

·or ·example, we'te in the dassroom. There are some heavy tabtes. I think a fri end is going to tift ~hem. I give a warning. ~you try to Ifft those rabies on your own. you'll hurt yourself '

Same situation. Nobody is thinking of lifting the tables. I make a comment . -rrose rabies look beavyl If you tried to lift them, you 'd hurt yourself.'

Co mplete the answers using the word or words in capitals.

a Wha~ happ m when you heat water l l 0°C?

Wf OU h~a.r wa·htr .f-o I oo· c' i-l- boi[~'

b 'Whal doe water lum inlo "'ht~o ou boil iL?

[f OU .....

c Whan happen when you cool th t • m?

If OU ...

d Whal happens w1Pn you Ii aJ a pkcc uf rnct;d?

ff rou ..... " "

E Wha.t happens when you freeze pl ce of metal. lr OU

f \o\rJiat h(1ppens. when you Ereeze water? ff O·U .... , , .. , .... , .. , , ........... .

BOIL

'U .!.AM

TURN DACK

P. ' PA IJ

CONTRACT

EXPANDS

Use the words to complete an if-5entcence about solutions to environmental proble m).

Solutillli A - recyde paper, rll~tai mtd g/as.<:.

a v ryon I r · d paper I coinpanie I not cut down so many 11 .es 1-" .e.ve.rtjoM. re..ctjc.le.s ptlpe;.r, .. cmup.ruti~s wmt 1-t- cu+ do.wr- so JMnlj. -l-rte.s.

b everyone I recyi::le meta l and gla • / we not waste v;;iluable resources

c everyone I re yd paper, metal and glas.s I w not produce so much rubbish

Sa/Litinn B - tum off light.~, don 't drive ~D mm;h, insulate ynur hou.'!e:

d everyon I tum off unwant d Ughl:S I ave lot of ele tri ity

e everyone/ walk or cyc1 I not waste so much ol I aad p trol

f everyone f insulate their hou es I nol wasLe so 1nuch energy for heating

Solution - 11.se renewable energy

g countries use more wind and water po er, not depend o much on pow r tatlon

h · ou 111 ries u powe1· ta lion le s, cause less <tJ:r pollution

3 Use the prompts to omplete the question. Then choose the most likely answer. Check the factual answers on page 208.

a what I happ n i 1 you I tra l through the

Earth to the oilier side .

. Uha . .f- uJati d kappe.rt_i.f ljOU -lrave.Ue.d fhrv~ +he. ~l<{rfk to .+he. other side.'?

b "'hat / happen if th /.".arth uddenl · Lop

{ going row1<l?

c whm I happen U we no I have a Moon?

d li . hat I happ n if all the iti! at the poles. / melt?

e what/ l1appen if thCiii;' be I no mor electrklty't

f what I happen ll a 1 ns receive I me s ges frou1 Eaith and de ide I L"o vi H us?

a A Yo11 wo1d l flJ' out Ire

other id iur:o pace.

b A VI e rwo111d cnjo · 1on. er

aud warm r, fa)'

c A The;re wo11/t/ noi be any

or:eau ti le .

d A err levd5 wauld fall.

e A 'flm 1mi11er~e wm1/d no

longer e~"tfis t .

f A Tl1ey wou1d11't know

cxa lly w~wr ' ~ e ~wre.

B 1i1i wo11ld 1Je Imp Ible

becmise tl1e £arch' cori.i is lioc.

B It wo11ld tart movin in tire opp.a iti firoction

B Tire Eart/1 would spin rnore

fowl

B ea lcvd · wa111r/ lar lhc llmr!.

S 11enple wn11lt1 u.'i" rnmltes (Or

lfrrhi and fire· fi_ir lleat.

B Thu}' 1. ouldr1t an'ive for

rnlllicms n/)ew:~, a. llu:y would be o far ow ,v.

C You wo11id {I II to rll entre

and rfhm top.

c fl.•e11 ff the EarUI topped, we

wmd 1 keep movi11 I

C Tl1e Srm would gmw " hm1gcr.

C e 1 Je11el.s wu11/tJ ri ·c,

C Tl1e world would be u safer

JI/ace.

C TIU:}' wouf,tn't cmd rsrm1rl

ow me.~.~a.~ ' ,m ;.11ay.

4A Rewrite each sentence so that it c:ontains unle:s-s or as long as and begins as ~hown.

a I ou don't train hard, you ·won't succeed in · port.

Yuu W'OI'\ '.f- St!CC.ud irt S-por.f- ~11.!~SS /.jOt.I .f-rti.i~ k~rd, b H you train regi larly, · ou can imp ve our p rfom1ance.

You can impro e .. _ ........ _ .... -·· ·~ ... ... . . c: H ou e.njo ou.r sporL, i.l doesn ' t r@all ma!ter whe.Lhe.r ou ·uc eed or nnl.

It doe n't te~lly matter

d you don't e ·t and leep properly yo won' develop as an athlete. You won't

-B R.ewrite each sentence so that it contains in case.

e ake par pair of runnin l1oes1 becau e it' · possible th t you will ne d th m.

ak spare pair of running sl10 -

t Thke · Wilterproof coal wi h you because it' · possible lhat it iU rain.

a k a wa terpro f at wi h you g la.ke a wann Jumper beca.u e it's possible Lhat ou will get old when ou ·top ..

k • · w rm jumper

h ir t-aid t.:il be au c It' po ible that nleone will get lnjur d.

Take a fir t-c id kit

5 Use the words to complete the conditional if-sentence. Use an always true, rea l o·r unrnal conditional to suit the meaning.

a i nti 1 are plannin a wa o writin xtremel m lJ I u .1 1 u in . n n (Xe) atom . U

y u (us J.1S£.d Lhis tem, you (bi! abl ) t of the

n1 hit' on I he area n!' il pn<;t,1ge stamp.

b Humans are among the few animals to have colour vision. If u b a hone,

for 1-xampl , y u ( e everythin J in black and """hite. c he hrain works in lwo parts, Lhe left . Ide a nd lhe rigllt side .. cien Li l!i can put one ide of

the brain to sleep, ::md see what happens. For example, i the tum off) the

right id of th patient . brain, the patient not be able ·o In , be<:au c

musical abili't corn [mm the right ide of the bnin.

d Beetles ar one ol b mos nume ous sp ie5 on the planf't. In fact, if oth r insect and

animal not cat) bl!ctlcs, iu uuuut a y!!ar <rnd a hall U1e beetle population

(w i h) a much a th whole llard !

e Parts 01· the bod · send messages to other parts of the body wh n they hav to do thing ,

ur · amp! 1

1 ll ou 1101 ha c) enough wate in our bod, the brain l]et)

y u know that you need more, b making you cl thirst .

f If y u look) ....... ·" .. .. . in lde your own eye at the image there. th y e) up -j,l down, and the (be)

g If you ( moke)

mo in~.

. , chern!GJI change (take pfac )

which do not re eiv enou.iTh oxygen and d~e .

h Thi:! world's oce.an contain hu e amount of alt. In fact, lI ou (remove

in · our t:!!ll ,,

all th S'1lt from lhe oceans, ou (b able to use it t(l bui Id . wall about JOO kn'I wide and

a kllometr taJl aII around the: Earth.

EXTENSION ACTIVITY

1 Write five enten es about your life which begin UnfeM> I .. •

2 Write a list of eight interesting scientific facts you found in this unit, which begin If ...

Need more µrachLe? Go to tlw Rt~view on page 192.