Of the system upon with drawings was taught by the Egyptian masters, we know nothing.
(1) It was a learning experience to determine the general proportions of the body, and the invariable relations of the various parts one with another; but they never troubled themselves to tabulate those proportions, or (2) reducing them to a system. Nothing in what remains to us of their (3) works that justify the belief that they ever possessed a canon based upon the length of the human finger or foot. Theirs was a teaching of routine, and not of theory.
1. For the sake of clarity of expression and meaning, the underlined portion of the sentence should be written as follows:
(A) as it is now
(B) Learning experience determining
(C) Learning experience, determining
(D) They had learned from experience to determine
2. (A) NO CHANGE
(B) to reduce
(C) having reduced
(D) have to reduce
3. (A) NO CHANGE
(B) works justifies
(C) working justifies
(D) workings justify
1. (D). They had learned from experience to determine.
This choice creates a grammatical sentence that follows logically from the preceding sentence. In this choice, "they" refers to the "Egyptian masters" in the previous sentence. Both sentences are correctly cast in the past tense. The other choices do not create grammatical sentence that make good sense.
2. (B). to reduce
This choice makes good grammatical sense. Note that the infinitive phrase "to reduce them to a system," like the preceding infinitive phrase "to tabulate those properties," is the object of the verb "troubled." None of the other choices create a grammatical sentence.
3. (B). works justifies.
The adjective prepositional phrase "in what remains to us of their work" modifies the noun "nothing," which is the subject of the sentence. "Justifies" is the correct verb form because it agrees in number with the subject, "nothing."