prep 59关于指代

yaozo

among ....is believed to be the rate at which trees grow, as seen in the rings visible in the cross sections of their trunks.

1). 介词短语置前则倒装。the rate显然是主语。
2). as seen 修饰就近的trees更合理， 而不是C答案中的sunspot cycles. 这样their trunks中的their指代trees也很自然。

phenomena

以下是引用cecilechina19在2007-6-13 12:20:00的发言：

我在想E选项可以改写成这样吗？--------

The rate of which trees grow is believed to among the surest indications on Earth of sunspot cycles

我觉得应该是：

As seen in the rings visible in the cross sections of their trunks, the rate at which trees grow is believed to be among the surest indications on Earth of sunspot cycles.

这里的“be among”感觉是看出首否倒装的一个障碍，因为一般倒装很少看到表语是介词短语的系表结构。