2.2. Two friends talking in a cafe

– I ˈwouldn’t ˙mind a‘nother cup of _\tea. It’s ^↘so ‘comfortable ‚here.

– ‘Yes, it’s a ‘nice ‚cafe. But I’m a‘fraid we shall ^↘have to _\leave.

– ¯Oh, _\Kate, ¯just a _\few minutes ‚more ...

– ¯All ‚right. But ˈdon’t be ˙late for the ˇtrain.

c) sphere of communication varied, subject-matter and social status un­changed;

1. Teacher at school introducing new material in a geometry class

If you have a ˈstereo˙metrical ‚figure – we’ll ˌcall it _\F – and we ˈwant to _\move it from its o‘riginal po‚sition in _\space, which we’ll ˈcall ˈS_/1 into a ‘different poˌsition which we ˌcall ˈS_\/2,│ >then ¦ we can ˈsee that there are ‘two ˌways in which we can _\do this. There are ˈtwo _\cases.

The ‘first case ‚is that ¦ you can ˈmake this ‘movement ¦ from ˈS_/1 to ˈS_/2 ˈby ˙means of a “motion│ which we’ll ˌcall a ˙transˆlation,│ ¯trans_\lation ¦ ˌmeans a _\motion and it ˌmeans a ‚motion which is “parallel to itself.

‚Or ¯it can be ‚made ˙by ˌro‘tation,│ ‚or ¯it can be ‚made ˙by а ˈheli‘coidal ˌmotion│–ˈheli‚coidal ˙motion is a ˈcombi_\nation of a ˌtrans‚lation│ and ¦ ¯a ro_\tation. ˌAnd ¦ ˈin ¦ po_\sitions ˈS_/1 and ˈS_/2│ the figure reˈmains “congruent with itˌself. You ‘know what ‘_\congruent’ with itself ˌmeans, _\don’t you?

2. A lecture to college students

If a ˈstereo‘metrical ‘figure ‚F│ be ˈbrought from its o“riginal poˇsition in ˈspace ˙S_/1│ˌinto ¦ a ‘different ро‚sition ˈS_/2,│ ˈtwo ‚cases will be dis_\tinguished. The ‘first ‚case is ¯that ¦ the ¯tran‘sition from ˈS_/1 to ˈS_/2│¯can be ‚made ˈby ¦ ˈmeans of a ‘motion│ ‘that ‚is, by a ˙trans‘lation,│ a ˈshift ˇparallel to itself,│ by ˈroˇtation or ‚by ¦ a ˈheli‚coidal ‘motion, ˈthis ˌbeing a ˈcombination of the two ‘former. In the poˇsitions ˈS_/1 and ˈS_/2│the ^↘figure ^↘thus re‚mains ˇcongruent with it_\self. ˈLet us supˇpose that this disˈtinction ˙seems ‘simple eˌnough│ but it ˈcarries ˇconsequences ˈvery “far from _\simple.

POETRY

The Arrow and the Song ♫

I ˈshot an ‘arrow ˌinto the _\air,

It ˈfell to _\earth, I ˌknow ˈnot ‘where;

For, so ‘swiftly it ‘flew, the ˈsight│

ˌCould not ‘follow it│in its _\flight.

I ˈbreathed a ‘song ˌinto the _\air,

It ˈfell to _\earth, I ˈknew ˈnot _\where;

For ˈwho│has _\sight so ˈkeen and ‘strong

That it can ˈfollow the ˈflights of _\song.

ˈLong, ˙long ‘afterward, in an ‘oak

I ‘found the ‘arrow, ˈstill un_\broken;

And the ˈsong, from beˈginning to ‘end,

I ˈfound a’gain│in the ˈheart of a _\friend.

H. W. Longfellow (1807-1882)