以下是引用guandream在2004-1-11 8:33:00的发言: main clause action dependent clause action 1 while, as , when short long
2 while, as long long 3 (just) as, (just) when short short
explanation: short action: ring open; long action: walking, talking. in situation2: as: two situations which develop or change together. As I get older, I get more optimistic. while: two actions happen at the same time. while you are reading the information, I am working. when: refer to ages and periods of time. when I was a child, we in in london.
the information above comes from grammar usage book. I think it is clear. if you have other opinions, we can discuss it.
it is just grammar, but for GMAT, in my opinion, the most important is clear and effictive. "as" can be time and cause conjunction; "while" can be time and comparison conjuction. thus, "when" is best choice for the time clause, even though the differences exist. on the other hand, "as" is very common to use in the time clause when two actions correlate or develop at the same time. |