在职攻硕英语考试

【单选题】 What is the summertime polar cap composed of
A．Dust.
B．Sand.
C．Water ice.
D．Volcanic rocks.

网考网参考答案：C
网考网解析：
[注释] 见第一段最后一句Previous spacecraft observations have shown that this summertime polar cap is composed of water ice，just like Earth's polar caps． 查看试题解析出处>>