Navigators have known for thousands of years that the ocean has variable currents, but it is only in the last half century that a reasonably clear picture has emerged of the patterns and causes of ocean currents. A a reasonably clear picture has emerged of the patterns and causes of ocean currents. B a reasonably clear picture of the patterns of ocean currents and their causes have emerged. C a reasonably clear picture emerged of ocean currents, their patterns and the causes of them D there have emerged a reasonably clear picture of the patterns of ocean currents and what caused them. E there had emerged a reasonably clear picture of the patterns of ocean currents and their causes.
I see now, the original statement should be like this:
Navigators have known for thousands of years that the ocean has variable currents, but it is only in the last half century that a reasonably clear picture of the patterns and causes of ocean currents has emerged.
But b/c the bold faced part is too long, so they switch it to the end. That's why choice A is correct.
For thousands of years, navigators have known that there are different kinds of currents, but they did not understand and did not have a clear picture of the patterns of those currents, until the last 50 years.
qingqinghu, does that make sense to you now?
Could someone please type it in Chinese? otherwise it will cost me 30 minutes to do so.
京公网安备11010202008513号 京ICP证101109号 京ICP备12012021号
发表于 2006-7-15 12:44:00
楼主
