单项选择题

The purpose of the scientists in studying tree rings is to （）。

A. examine the chemical elements in the Ice Age
B. look into the pattern of solar wind activity
C. analyze the pattern of solar wind activity
D. find out the origin of carbon-14 on earth

<上一题目录下一题>

热门试题

问答题

The washing machine manufactured in out factory is light in weight, small in size and good in quality.

单项选择题

Of the risky activities, bungee jumping （）.

A. offers an immediate excitement
B. is a fashion
C. makes one relaxed
D. makes one brave