CH@RMEDgirl said:
Hi, I would like to receive an explanation about the WH~QUESTIONS + PREPOSITIONS, for instance:
WHAT is a pen FOR?
WHAT channel is Susan working IN?
I would like to know when i am supposed to do this, why and how?
What is a pen for? means, what is a pen
used for? Notice that 'for' modifies 'used'.
Q: What is a pen
(used) for?
A: A pen is
(used) for writing.
If a word like 'for' comes after the word it modifies, it's part of that word, and so it doesn't move unless the word it modifies also moves. For example:
Sentence: A pen is used for writing.
1) [WH-replacement] A pen is used for
what
2) [WH-movement]
what a pen is used for
3) [Subject-Verb inversion] what
is a pen used for
Question: What is a pen used for?
'for' doesn't move with 'what' (i.e. *
For what is a pen? ungrammatical) because 'for' does not modify 'what'. It modifies 'used': 'used for' is a set phrase.
'for' is a particle, not a preposition. The same holds true for 'work in':
Sue is
working in TV.
In what is Sue working? (
ungrammatical)
What is Sue working in? (
grammatical; 'work in' is a set phrase; 'in' functions as a particle, not as a preposition)
If a preposition modifies a noun, the set pair forms a prepositional phrase (PP). Within that phrase, only the noun can be replaced by WH. After WH-replacement, the speaker has two choices: either move the entire PP or move the WH word, like this,
Sentence: She gave the pen to Sam.
1) [WH-replacement] She gave the pen to
whom
2) [
PP-movement]
to whom she gave the pen
3) [Do insertion] to whom
did she give the pen
Question: To whom did she give the pen?
Sentence: She gave the pen to Sam.
1) [WH-replacement] She gave the pen to
whom
2) [
WH-movement]
whom she gave the pen to
3) [DO insertion] whom
did she give the pen to
Question: Whom did she give the pen to?
Knowing when to move words like 'for' and 'in' and 'to' involves knowing what sets of words function as verb phrases, noun phrases, and prepositional phrases. A place to start: look up phrasal verbs.
Example:
She walked
up the hill.
Where did she walk? (Prepositional phrase, OK)
What did she
walk up? (
Noun phrase,
verb phrase, OK)
Up what did she walk? (
ungrammatical, not OK)
up = part of 'walk', it's a particle, not a preposition here. It needs to stay with 'walk'.