Kamis, 05 Mei 2011

Talking About Certainty

Must can be used to express the conclusion that something is certain or highly probable.

If A is older than B, and B is older is than C, then A must be older than C.
She must have a problem – she looks worried.
There is the doorbell. It must be your Dad.

To express certainty in questions, we usually use can. Note that must is not used in questions with this meaning.

There is the doorbell. Who can it be?

Cannot can be used in negative clauses to say that something is certainly not the case.

It can’t be the postman at the door. He has already been.

Need not can be used to say that something is not necessarily so. Must not is not used to express this meaning.

‘Look at those tracks. That must be a fox.’ ‘It needn’t necessarily be – it could be a dog.’

The structure must have + past participle is used to express conclusions about the past.

‘Somebody phoned while you were sleeping.’ ‘That must have been Peter.’
She must have reached home by now.

sumber : http://www.perfectyourenglish.com/speaking/english-speaking-certainty.htm

Selasa, 03 Mei 2011

Talking About a Limited Quantity of Something

To talk about a limited quantity of something we often use the word piece or bit, together with of, before an uncountable noun. Note that bit is informal and usually suggests a small quantity.

The most common expressions of this kind are:

A piece / bit of cake / bread
A piece / bit of paper / wood
A piece / bit of news / information
A piece of advice
A piece of spaghetti
A piece of furniture
A piece of luggage

Other words like bar, blade, drop etc are also used. But note that they are less general and are used before particular nouns. Some common examples are:

A bar of chocolate / soap
A blade of grass
A block of ice
A drop of water /oil
A grain of salt / rice / sand / corn
An item of clothing / furniture
A loaf of bread
A slice of bread / cake / meat
A lump of sugar / coal
A speck of dust
A sheet of paper / metal / plastic / stamps
A stick of chalk
A strip of land / water
A suit of clothes


Pair is used for many things that normally come in pairs. Examples are:

A pair of shoes / socks / ear-rings
A pair of glasses / binoculars
A pair of trousers / jeans
A pair of scissors / pliers

sumber : http://www.perfectyourenglish.com/speaking/a-piece-of-something.htm