Are there any differences between "The police observed the man enter the bank." and "The police observed the man entering the bank. " Does sentence one mean that the police observed the whole process that the man enter the bank? Does sentence two mean that the police observe the action of the man entering the bank? One emphasize the whole process and the other emphasize the exact action of entering. Am I right?
Thank you very much!
This is not the best example. Since 'entering' is not something a person can just partially do (they either enter or they don't, like being pregnant), the contrast is not very strong. As such, whatever the police saw, they must have inferred that the process of the man entering the bank ran to its completion.
A better example would be
The police saw the man eating the hot dog.
vs.
The police saw the man eat the hot dog.
Both of these sentences report a fact in a very general way. In either case, whether the police saw the man finish eating the hot dog is an open question.
Note, however, that only the first of the following two is acceptable:
The police saw the man eat the hot dog and then leave.
The police saw the man eating the hot dog and then leave. (wrong)
You could say, however,
The police saw the man eating the hot dog finish [it] and then leave.
.....
Also, there is one special way in which the original sentences are different:
The sentence
The police observed the man entering the bank
can answer the question
Who(m) did the police observe?
but the other sentence cannot:
The police observed the man enter the bank* (wrong).
This is because "entering the bank" can be the complement to the verb "observed" (compare "I love entering the bank!") OR a modifier to the noun "man" (compare "People entering banks are usually in a bad mood.")
By contrast, "enter the bank" can ONLY be the complement to the verb "observed", since "the man enter the bank" makes no sense on its own as a noun phrase (compare "the man entering the bank")
There are complicated constraints on complex catenation constructions involving sensory perception / observation verbs.
I saw him enter the bank.
I saw him entering the bank.
At wordreference is the discussion:
I know that a verb expressing observation or perception can be only followed by a noun and a participial phrase (-ing). [WRONG]
But I've come across this (... from an English grammar book): 'A verb expressing observation/ perception can ... also [in some cases be] followed by a noun and a base verb form. [bare infinitive] There is [often] no [appreciable] difference in meaning.' examples:
1.We felt the temperature rising. - We felt it rise.
2.We observed [Mr Martin] doing open-heart surgery. - (no base-form equivalent)
(I've corrected glaring errors.)
Here is a reply:
"We observed [Mr Martin /] the doctor do open-heart surgery." That seems OK to me.
Though, to be honest, I really don't like "observe" with either form. That's probably a personal peculiarity.
Switching to the verb 'see' or 'watch' removes any problems here; both the complex -ing form and the complex bare infinitive are commonly used in such structures. Merk mentions the slight change in emphasis in using the continuous form (-ing). However, switching to 'film' or 'record', verbs not too far away semantically, surely removes the availability of the bare infinitive here:
"We filmed / recorded [Mr Martin /] the doctor doing open-heart surgery."
*"We filmed / recorded [Mr Martin /] the doctor do open-heart surgery."
There are numerous examples of the construction S observed X V ... on the internet; I think the bare-infinitive complex catenation cannot be labelled 'ungrammatical' nowadays (though I wouldn't use it).
In most situations, the difference is more style than substance, although the sentence "The police observed the man enter the bank." implies that a subsequent action happened after the man entered. The other sentence, "The police observed the man entering the bank.", seems to suggest that whatever comes next happened while the man was entering.
The verb observe, as far as I'm aware, cannot take a clause* as an object; therefore, the first sentence would be ungrammatical. (A sentence like The police watched the man enter the bank, though, would be fine.)
The second sentence can be read two ways, though one sounds more likely to my ears. The likelier interpretation would be that the police watched the act of entering the bank being performed by the man. Functionally, entering looks like a gerund — in one word, it's the entering that the police observed — though I don't think anyone would put a possessive in front of it.
The second possible interpretation is that the police observed the man who was entering the bank; in this case, entering functions as a participle. However, this sounds a bit strange. When used this way, the participle seems to act as a way to identify which person we're talking about (cf The police observed the man wearing the ridiculous hat; they didn't watch him wear a hat). Not that I've got around to tabulating the data, but I think that in most cases when I hear this construction, the lexical aspect of the verb from which we construct the gerund or participle suggests which verbal is in fact intended. Note that the verb enter has duration in more of meaningful sense than does wear; we can ask "How long did it take him to enter the bank?" but not "How long did it take him to wear that hat?" That's why I'd guess that the first interpretation is more likely.
* the man enter the bank is not a clause in the traditional-grammar sense. However, I believe I've seen the same construction called that in linguistics texts.
