2014-10-20 09:00:38

When Neville Chamberlain and others agreed to appease Adolf Hitler in 1938, they thought they had avoided a major war, only in retrospect did the agreement look like one of history's great blunders.

(A) they had avoided a major war, only in retrospect did the agreement look like one of history's great blunders
(B) a major war had been avoided, only in retrospect did the agreement look like one of the great blunders of history
(C) they had avoided a major war, but only in retrospect the agreement looked like one of the great blunders of history
(D) they had avoided a major war; only in retrospect did the agreement look like one of history's great blunders
(E) a major war had been avoided; but only in retrospect the agreement looked like one of history's great blunders

The correct choice is D
Explanation: As written, the underlined portion creates a run-on, as it links two independent clauses ("they thought... war" and "only in retrospect... blunders") using a comma alone. Choice D corrects this sentence structure error by replacing the errant comma with a semicolon.