Writing "adopted"

<p>I had difficulty with this writing question from the McGraw Hill book. In the nineteenth century, a few respected thinkers “became convinced”(A) that nations would not be able “to coexist” (B) peacefully “until” (C) all of the world’s cultures “adopted” (D) a single mutual language. “No error” (E)</p>

<p>The correct answer was choice E, “no error”. </p>

<p>I thought choice D was incorrect and should have been “would adopt” as its describing something that will occur in the future. How come the original sentence doesn’t need to be changed?</p>

<p>It makes sense if you shorten the sentence. </p>

<p>“In the 19th century, a few respected thinkers became convinced that nations wouldn’t be able to coexist peacefully until all the world’s cultures adopted a single language.”</p>

<p>By the time the nations would be peacefully coexisting in this example, the single language would have already been adopted.</p>

<p>Just think about it in another way … If you change ‘adopted’ with ‘would adopt’, won’t the sentence sound a bit awkward and funny?</p>