回答1.if there is not "but",whose-clause,will not parallel with who-clause,and it may refer to GM or JR or composer,who konws? ambiguity.
回答2.comma is not the point of GMAT ,if it is used here,I think that indicate"pause & turn".
just my two cents.hope that helps.
-- by 会员 shaoheng1120 (2011/11/25 22:25:09)