I'd like to ask about the interpretation of (1), though the author didn't mention that (1) is actually ambiguous.
(1) Who did Philby know that Angleton suspected?
(R. May, Logical Form)
Do you agree that (1) can be rewritten either as (2) or (3)?
(2) a. Who, [of/among] those Philby knew, did Angleton suspect?
b. Who did Philby know of that Angleton suspected?
(3) Who, [of/among] those Angleton suspected, did Philby know he suspected?
Thank you in advance
I'd appreciate it if you could also let us know the meaning of "know" of (3).