***** NOT A TEACHER *****
1. Welcome to usingenglish.com.
2. Thank you for teaching me the term "attributive clause." The Web told me that many people prefer the terms "adjective clause" or "relative clause."
3. This is the "Ask a Teacher" forum. When you have time, please check out the "Diagramming" forum. There is a teacher there who helps members parse (analyze) the parts of sentences, and he will even draw a diagram for you.
Regarding your sentence, may I offer some ideas (these are not "answers").
1. In my opinion, your sentence does not contain any adjective clauses.
2. In order to analyze your sentence, may I simplify it a bit?
All a VFR pilot has to do to enter Class C airspace is establish two-way radio contact.
That seems (to me) to mean:
The only thing (that a VCR pilot has to do to enter Class C airspace) + is + (to establish two-way radio contact).
a. In my opinion, "(that) a VCR pilot has to do to enter Class C airspace" is a noun/substantive clause in apposition with
"thing." (Some people might interpret it as an adjective clause. I disagree, for "that" in that sentence plays no
grammatical role. It is neither the subject nor the object. It only formally introduces the appositional clause.)
b. "is" is a linking verb. It links (connects) "all" (the only thing) with "(to) establish two-way radio contact with ATC."
(You can delete (drop) "to" if you want to.)
c. In my opinion, we can parse "(to) establish two-way radio contact with ATC" as the subjective complement of
"all." That is, all (the only thing) = to establish two-way radio contact with ATC.
(OR: To establish two-way radio contact with ATC is all a VFR pilot has to do to enter Class C airspace.)
d. "radio contact." As you can see, the noun "radio" modifies the noun "contact." If you want to, I think (repeat: think)
that you can call "radio" a so-called "attributive noun," but surely NOT an attributive "clause."
e. In my opinion, "two-way" modifies "radio contact." That is, "radio contact is two ways." I do not know what to call
"two-way" in your sentence except a compound adjective.
f. "contact with ATC" = the prepositional phrase "with ATC" modifies "contact."
g. Finally, as to the predicate of the sentence. As you know, a sentence has two parts: the subject and the predicate
(which is defined as everything except the subject): "I love newspapers." ("I" = subject; "love newspapers" = predicate).
"All a pilot has to do to enter Class C airspace" (subject)"
"is establish two-way radio contact with ATC." (predicate).
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