I have asked the same question in ELL stackexchange, but unfortunately haven't received enough answer/comment. The one answer I got is not satisfactory. So that's the reason I am asking it here again. Link to ELL post.
I have seen in some cases prepositions are omitted before some noun phrases. And it's explained that those phrases are actually an adverb phrases. But I know a simple thing. If the head of the phrase is a noun, it's a noun phrase. If the head of the phrase is an adverb it is an adverb phrase.
For example –
Look both ways before crossing the road. [both ways is a noun phrase, where the head is ways, but still there is no preposition.]
He approached me in a friendly way. [a friendly way is a noun phrase, where the head is way, but as expected unlike sentence #1 it's preceded by the preposition in. And I have never seen this phrase is used without a preposition. I believe dropping the preposition is wrong, according to the grammar.]
She made a pickle a different way from her mother. [a different way is a noun phrase, where the head is way, but strangely there is no preposition before it. But I have seen examples of a different way used both with prepositions and without prepositions. I think the preposition here is optional.]
Now from these example sentences I have tried to demonstrate my problem/confusing area. My question is –
1. When a noun phrase is used as an adverb phrase?
2. When before a noun phrase the placement of preposition is obligatory (like sentence #2)? And where it's optional (like sentence #3)? And where placing the preposition is wrong (like sentence #1)?
Best Answer
1# Look both ways. Commands telling someone where to look with way typically do not need a preposition: look my way, look this way, look the other way.
Conversely, (the much less likely) command telling someone which looking method to use can, but does not need to, have the preposition. So, look in both ways could mean something like: Look first with your left eye closed and then with both eyes half open. The preposition is optional here (in!) the same way that it is in example 3.
2# He approached me in a friendly way. In this case, the phrase in an [adjective] way means in an [adjective] manner. For example, in a suspicious way, in a hesitant way, in a confident way. It seems that the in is not optional when way has this sense.
3# She made a pickle a different way. Here way is synonymous with method. And it appears that the in is optional in such contexts. Omitting the preposition when way means method renders the language more informal. This is what Swan in Practical English Usage (p606) says: