标题: og 16 29题review 遇到问题 [打印本页] 作者: 白冬冬 时间: 2016-6-12 22:48 标题: og 16 29题review 遇到问题 By 1940, the pilot Jacqueline Cochran held seventeen official national and international speed records, and she earned them at a time when aviation was still so new for many of the planes she flew to be of dangerously experimental design.
A and she earned them at a time when avation was still so new for many of the planes she flew to be
B earning them at a time that aviation was still so new for many of the planes she flew were
C earning these at a time where aviation was still so new that many of the planes she flew were
D earned at a time in which aviation was still so new such that many of the planes she flew were
E earned at a time when aviation was still so new that many of the planes she flew were
问题： by＋time, 为何出现了一般过去时？
Ron：
in clauses modified with "by TIME", you should use
the past perfect (had VERBed) if the time marker is in the past
the future perfect (will have VERBed) if the time marker is in the future
if the time marker is "by now", then you should use the present perfect, but that's unlikely to come up in a gmat problem. （http://www.beatthegmat.com/present-perfect-and-past-perfect-usage-summarized-t49438.html）