Page 465 - Practical English Usage 3ed - Michael Swan, Oxford

prepositions (4): expressions without prepositions 451
5 Whattime...?etc
We usually leave out at before what time. What time does Granny's train arrive?
(More natural than At what time ...? )
In an informal style. we can also leave out on before what!which day(s).
What day is your hair appointment? Which day do you have your music lesson?
6 about
In an informal style. at is often dropped before about + time expression.
I'll see you (at) about 3 o'clock.
7 'how long'
In an informal style, for is often left out in expressions that say how long something lasts.
I've been here (for) three weeks now. How long are you staying (jor)?
8 measurement expressions etc after be
Expressions containing words like height, weight, length, size, shape, age, colour are usually connected to the subject of the clause by the verb be, without a preposition.
He is just the right height to be a policeman. She's the same age as me.
His head's a funny shape.
I'm the same weight as I was twenty years ago. What shoe size are you?
What colour are her eyes? (NOT Of ttthat eBitHtF ••• ?)
9 (in) this way etc
We often leave out in (especially in informal speech) in expressions like (in) this way, (in) the same way, (in) another way etc.
They plant corn (in) the same way their ancestors used to 500 years ago.
10 home
We do not use to before home (see 249). I'm going home.
In informal English (especially American), at can be left out before home. Is anybody home?
11 place
In an informal style, to can be dropped in some expressions with the word place. This is normal in American English.
Let's go (to) some place where it's quiet.
I always said you'd go places. (= become successful)
12 infinitive structures
Prepositions can be dropped in the structure noun + infinitive + preposition (see 285.5).
She has no money to buy food (with). We have an hour to do it (in).
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