02-08-38 pp-1-6 过几天就要考试了， 有几道题不懂， 请指教， 急

1 perhaps the most significant postwar trend was the decentralization of cities throughout the united states ,_____when massive highway-building programs permitted greater suburban growth.

a a phenomenon that accelerated

b and accelerated a phenomenon

我想选的是b 但答案是a 不懂。请指教！

A其实是一个宾语从句省略结构the decentralization （which was）a phenomenon，而从句套的另一个when引导的从句结构清晰；若是选B，你看这个when引导的从句紧接a phenomenon，意思上不通～

2---------，domesticated grapes grow in clusters , range in color from pala green to black , and contain sugar in varying quantities.

a their botanical classification as berries

b classified botanically as berries

句子里面缺的是主语， 我想选a ， 但答案是b

句子不缺主语，domesticated做形容词，修饰句子主语grapes，请辨析清楚，B是一个状语从句的省略结构，正确。