A．the Indo­Pacific has the largest coral coverage

　　B．reefs only began to disappear in the 1960s

　　C．coral loss has only happened in some parts of the world

　　D．human factors play an important role in coral loss

　　解析　推理判断题。从文章第一段的介绍可知，珊瑚礁的消失与三个因素有关，而气候变暖和海岸开发都有人为因素在里面。

　　答案　D

　　42．In what way are coral reefs important?

　　A．Many marine plants and animals

　　live in them.

　　B．They can be used as building materials.

　　C．Many marine plants and animals feed on them.

　　D．They provide shelter for island residents.

　　解析　细节理解题。文章倒数第二段第一句说明，珊瑚礁为很多海洋动植物提供了“家”。

　　答案　A

　　C

　　How much rain has fallen on the earth in the past？Man has not always kept weather records.Because scientists need a way to learn about past rainfall，they study the tree rings.

　　A tree's trunk(树干)grows bigger each year.Under its bark(树皮)，a tree adds a layer of new wood each year it lives.If you look at a tree stump(树桩)，you can see the layers which are called annual rings.

　　On some trees，all of the rings are of the same width.But the ponderosa pine(美国黄松)that grows in the American southwest have rings in different width.The soil in the southwest is dry.The pines depend on rainfall for water.In a year of good

【2017届高考英语（重庆专用）二轮精练：选修9 unit4 Exploring plants单元测试】相关文章：

★ 2017届高考英语二轮复习课时训练：2（含解析）

★ 【人教版】2014届高考英语一轮复习指导考点针对练：选修6 unit4《Global warming》

★ 2017届高考英语二轮复习课时训练：1（含解析）

★ 【北京专用】2014届高考英语一轮复习方案课时作业：必修1 Unit 3 Travel journal

★ 【三维设计】2017届高考英语（江苏专用）二轮复习素材：高考单词2.背佳句记单词

★ 2014高考英语（新人教版）一轮基础训练（6）A、B卷（附答案或解析）

★ 2017届高考英语二轮复习课时训练：17（含解析）

★ 2014高考英语（新人教版）一轮基础训练（8）A、B卷（附答案或解析）

★ 【三维设计】2017届高考英语（江苏专用）二轮复习完形填空解题技法示范课件：4

★ 【课堂新坐标】2017届高考英语（通用版）二轮复习书面表达专题训练：Ⅱ卷强化增分练 训练1（含解析）