GMATCLUB Ultimate Grammar: Q. No. 28 (Practice test 1)

I'm happy to help with this.

First, if I may give some advice --- when you post a question, please indicate the OA in a "spoiler", as I did above. That way, others have the opportunity to think through the question fresh on their own, withing seeing the answer right away, and then they can check their work against the answer by checking the spoiler.

The word "another" is used for clarification. We don't know the details of this voting process. In some voting processes (ranked choice voting, MLB All-Star ballots, etc.) each person can vote more than one time as part of the process, while in many other systems, each person gets one and only one vote. We don't know at the outset which kind of system this particular class is using. The word "another" makes clear ---- 2/3 voted for the zoo, and between these folks and the 1/3 who voted for the amusement part, there is absolutely no overlap. That makes clear (a) each person did in fact cast one and only one vote, and (b) essentially no one was left to vote for anything other than one of those two options: in other words, those were the only two options considered seriously in this process. Without the word "another", we would be left guessing about the details of the vote and about whether there was any overlap between the 2/3 and the 1/3.

Use of the word "while" is more subtle. If our emphasis were the contrast --- some folks wanted the zoo, but other folks with very different sensibilities wanted the amusement part: wow, those two kinds of students are so different! ---- then we certainly would need a contrast word. Here, though, we are describing the voting outcomes in order to explain the decision made about where the class went. Both parts of the voting play into that decision. We are not emphasizing the contrast --- that is not the point of the sentence. Rather, we are presenting both sides of the vote equally, as an explanation of why a subsequent decision was made. That's why we have to join the first two phrase by "and", a joining word, not "but" or "while", which are contrast words.

Does all this make sense?

Mike