扫描二维码，直接登录
题库 / Prep2007E1-SC-139
On Earth, among the surest indications of sunspot cycles are believed to be the rate that trees grow, as seen in the rings visible in the cross sections of their trunks.
On Earth, among the surest indications of sunspot cycles are believed to be the rate that trees grow
On Earth, among the surest indications of sunspot cycles are, it is believed, the rate of tree growth
On Earth, the rate at which trees grow is believed to be among the surest indications of sunspot cycles
Among the surest indications on Earth of sunspot cycles, believed to be the tree growth rate
Among the surest indications on Earth of sunspot cycles is believed to be the rate at which trees grow
还没有题目讲解（毕出老师会陆续发布对官方考题的解读，请保持关注）。
among倒装，主语应该是the rate，所以应该用单数is
on earth 放置句首修饰整个句子，不符合逻辑，这里修饰动词believe是不对的
登录 或 注册 后可以参加讨论