42. What are the first two paragraphs mainly about?
- A. The various patterns at the ocean surface.
- B. The cause of the changes in ocean colour.
- C. The way light reflects off marine organisms.
- D. The efforts to fuel the growth of phytoplankton.
答案：B
答案句：By the end of the century, if not sooner, the world’s oceans will be bluer and greener thanks to a warming climate, according to a new study. … At the heart of the phenomenon lie tiny marine microorganisms(海洋微生物)called phytoplankton. Because of the way light reflects off the organisms, these phytoplankton create colourful patterns at the ocean surface. Ocean colour varies from green to blue, depending on the type and concentration of phytoplankton. Climate change will fuel the growth of phytoplankton in some areas, while reducing it in other spots, leading to changes in the ocean’s appearance.
参考译文：根据一项新研究，到本世纪末，如果不是更早的话，由于气候变暖，世界上的海洋将变得更蓝、更绿。… 这一现象的核心是被称为浮游植物的微小海洋微生物。由于光线从这些生物体上反射的方式，这些浮游植物在海洋表面形成了五彩斑斓的图案。海洋颜色从绿色到蓝色不等，取决于浮游植物的类型和浓度。气候变化将促进某些地区浮游植物的生长，同时减少其他地区的浮游植物，从而导致海洋外观的变化。
定位线索：题干“first two paragraphs mainly about”定位到第1、2段；文中“Climate change will fuel the growth of phytoplankton in some areas, while reducing it in other spots, leading to changes in the ocean’s appearance”对应选项B“The cause of the changes in ocean colour”。
解析：题干问前两段的主旨。第1段提出海洋颜色变化的现象，第2段解释其原因是浮游植物受气候变化影响，导致海洋外观改变。选项B“海洋颜色变化的原因”正是对第2段最后一句的同义转述。选项A、C只是细节，选项D“促进浮游植物生长的努力”在文中未提及，属于无中生有。
43. What does the underlined word “vulnerable” in Paragraph 3 probably mean?
- A. Sensitive.
- B. Beneficial.
- C. Significant.
- D. Unnoticeable.
答案：A
答案句：But phytoplankton are vulnerable to the ocean’s warming trend. Warming changes key characteristics of the ocean and can affect phytoplankton growth, since they need not only sunlight and carbon dioxide to grow, but also nutrients.
参考译文：但是浮游植物容易受到海洋变暖趋势的影响。变暖改变了海洋的关键特征，并可能影响浮游植物的生长，因为它们生长不仅需要阳光和二氧化碳，还需要营养物质。
定位线索：题干“vulnerable”在Paragraph 3；文中“Warming changes key characteristics of the ocean and can affect phytoplankton growth”说明浮游植物易受影响，对应选项A“Sensitive”。
解析：词义题需结合上下文。答案句指出变暖改变海洋特征并影响浮游植物生长，说明浮游植物对变暖“敏感”。选项A“Sensitive”是“vulnerable”的同义改写。选项B“有益的”、C“重要的”、D“不明显的”均不符合语境，属于偷换概念。
44. What can we learn from the passage?
- A. Phytoplankton play a declining role in the marine ecosystem.
- B. Dutkiewicz’s model aims to project phytoplankton changes.
- C. Phytoplankton have been used to control global climate.
- D. Oceans with more phytoplankton may appear greener.
答案：D
答案句：The model projects that currently blue areas with little phytoplankton could become even bluer. But in some waters, such as those of the Arctic, a warming will make conditions riper for phytoplankton, and these areas will turn greener.
参考译文：该模型预测，目前浮游植物稀少的蓝色区域可能会变得更蓝。但在一些水域，如北极地区，变暖将使条件更适合浮游植物生长，这些区域将变得更绿。
定位线索：题干“learn from the passage”定位到第4段；文中“a warming will make conditions riper for phytoplankton, and these areas will turn greener”对应选项D“Oceans with more phytoplankton may appear greener”。
解析：推理题需依据原文推断。答案句说明变暖使北极等水域更适合浮游植物生长，区域变绿，可推出浮游植物多的海洋可能更绿，选项D正确。选项A“浮游植物作用下降”文中未提；选项B“模型旨在预测浮游植物变化”偷换概念，模型是预测海洋颜色变化；选项C“浮游植物已被用于控制全球气候”程度过重，文中只说其有助于调节气候。
45. What is the main purpose of the passage?
- A. To assess the consequences of ocean colour changes.
- B. To analyse the composition of the ocean food chain.
- C. To explain the effects of climate change on oceans.
- D. To introduce a new method to study phytoplankton.
答案：C
答案句：By the end of the century, if not sooner, the world’s oceans will be bluer and greener thanks to a warming climate, according to a new study. … Climate change will fuel the growth of phytoplankton in some areas, while reducing it in other spots, leading to changes in the ocean’s appearance. … Warming changes key characteristics of the ocean and can affect phytoplankton growth, since they need not only sunlight and carbon dioxide to grow, but also nutrients. … In a world that warms up by 3℃, it found that multiple changes to the colour of the oceans would occur.
参考译文：根据一项新研究，到本世纪末，如果不是更早的话，由于气候变暖，世界上的海洋将变得更蓝、更绿。… 气候变化将促进某些地区浮游植物的生长，同时减少其他地区的浮游植物，从而导致海洋外观的变化。… 变暖改变了海洋的关键特征，并可能影响浮游植物的生长，因为它们生长不仅需要阳光和二氧化碳，还需要营养物质。… 在一个升温3℃的世界里，研究发现海洋颜色会发生多种变化。
定位线索：题干“main purpose”定位全文；文中“thanks to a warming climate”“Climate change will fuel”“Warming changes”等反复强调气候变化对海洋的影响，对应选项C“To explain the effects of climate change on oceans”。
解析：主旨题需概括全文目的。文章从海洋颜色变化引入，解释气候变化如何影响浮游植物进而改变海洋，选项C“解释气候变化对海洋的影响”准确概括。选项A“评估海洋颜色变化的后果”范围过窄；选项B“分析海洋食物链组成”文中未提；选项D“介绍研究浮游植物的新方法”答非所问，文章重点是气候变化而非方法。