Page 264 - Practical English Usage 3ed - Michael Swan, Oxford

Let me know whenlwherelwhatlhow ... The best thing would be to . . .
The point is . . .
I wouldn't be surprised if. . .
(00 something) as a favour.
. .. is more trouble than it's worth. I'll ... on condition that you.
idioms, collocations and fixed expressions 255
4 situational language: fixed expressions
The expressions that are used in typical everyday situations are often idiomatic in the same sense. With the help of a dictionary and a grammar, one could invent various possible ways of expressing a particular common idea, but generally there are only one or two ways that happen to be used by English speakers, and one has to know what they are in order to speak or write naturally. Some examples:
Could you check the oil? (More natural than Could you inspect the oil? or Could you see how much oil there is in the engine?)
Is it a direct flight or 00 I have to change? (More natural than Does the plane go straight there or 00 I have to get another one?)
Sony I kept you waiting. (More natural than Sorry I made you wait.) Could I reserve a table for three for eight o'clock? (More natural than Could
you keep me a table for three persons for eight o'clock?)
Other fixed expressions are used as parts of sentences - useful introductions, conclusions or frames for the things that people want to say.
5 using idioms, collocations and fixed expressions.
Idioms, collocations and fixed expressions are common in all kinds of English, formal and informal, spoken and written. Infonnal spoken language is often very idiomatic.
Students should not worry because they do not know all the expressions of this kind that are commonly used by English speakers. If they use non- idiomatic ways of expressing ideas, they will normally be understood, and English speakers do not expect foreigners to speak perfect natural English. It is therefore not necessary for students to make great efforts to memorise idioms, collocations etc: they will learn the most common ones naturally along with the rest of their English. In particular, note that books of idioms often contain expressions which are slangy, rare or out of date, and which students should avoid unless they understand exactly how and when the expressions are used. This is especially true of colourful idioms like, for example, raining cats and dogs, as cross as two sticks (= angry) or kick the bucket (= die). If students try consciously to fill their speech and writing with such expressions the effect will probably be very strange.
It is, however, helpful for learners to have a good up-to-date dictionary of collocations (for example the Oxford Dictionary o f Collocations) in order to become aware of the most common word combinations.
For more about formal and informal language. see 311. For slang, see 533.
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