"If two Weeping Angels were to look at each other at the same time, they would be trapped in stone form until an outside force moves them apart."
My questions are about the phrase "were to look":
- What's the meaning?
Your example sentence is in the form of a remote conditional construction. The remote conditional is used to show that there is modal remoteness, or unlikeliness, of a situation to occur. Your example is similar in meaning to the version that uses "looked":
"If two Weeping Angels were to look at each other at the same time, they would be trapped in stone form until an outside force moves them apart." -- [REMOTE Conditional--the OP's original example]
"If two Weeping Angels looked at each other at the same time, they would be trapped in stone form until an outside force moves them apart." -- [REMOTE Conditional]
Both of the above remote conditional versions have the same meaning, but the "were to look" version (which uses a quasi-modal BE) has a slightly stronger implicature of unlikelihood (2002 CGEL, page 753).
- What's the differences between it and just one word "look".
The version with "look" (instead of "were to look" or "looked") is an open conditional construction, where no judgement is being made as to the likeliness or unlikeliness of a situation to occur. This is what your open conditional would look like:
- "If two Weeping Angels look at each other at the same time, they will be trapped in stone form until an outside force moves them apart." -- [OPEN Conditional]
Notice in the above version that the past-tense "would" is replaced with the present-tense "will".
Be aware that there cannot be a corresponding open conditional version for your example that uses the present-tense phrase of "are to look". This is because the OP's example uses the quasi-modal BE verb. If the present-tense "are to look" was used, then the sentence would have a quite different meaning (2002 CGEL, page 151). And so, for the OP's example, there is only one open conditional version to correspond to the two remote conditional versions.
- In which section of my grammar book I can find this kind of usage?
Different grammars use different terminology. In the 2002 reference grammar by Huddleston and Pullum et al., The Cambridge Grammar of the English Language (CGEL), they used the terms: open conditional constructions, remote conditional constructions, conditional adjuncts, quasi-modal BE, "BE + infinitival", etc.
Traditional grammars use terminology that I think is confusing. Some EFL textbooks make up a whole lot of extra terminology. The grammar stuff on the internet, including wikipedia, seems to mostly be a mishmash of different grammars, and so, that too will be confusing.
ADDED: Info related to the phrase "BE to V", when the "BE" verb is in present-tense. CGEL page 753:
Protases with 'be + to' and should
i.a. (#) If it is to rain, I'll cancel the show. - - [open conditional]
i.b. If it were to rain, I'd cancel the show. - - [remote conditional]
ii.a-b . . .
There is an idiomatic use of what we call 'quasi-modal be' that occurs only in remote conditionals like [i.b]. In the open conditional If we are to survive we'll have to drastically reduce expenditures the protasis suggests purpose ("In order to survive, we'll have to drastically reduce expenditure"), which is why [i.a] is pragmatically anomalous.
In the remote conditional, this quasi-modal be serves merely to reinforce the remote meaning: the protasis of [i.b] means "if it rained" but with a slightly stronger implicature of unlikelihood. It occurs predominantly in future time protases. . . .