Question

【题目】阅读理解。

Even if trees cannot walk, they are still on the move.

In parts of the Arctic, entire forests are moving northward. Across the Arctic, temperatures are rising faster than anywhere else in the world. As that happens, the tree line that marks where forests stop and the treeless tundra (冻原) starts has been shifting northward. Trees growing along the tree line must protect themselves from the cold wind. To do this,_plants tend to grow horizontal (水平的) branches low to the ground. The energy it takes for trees to grow this way means they don't have enough energy to make seeds.

But as Earth's climate has been warming, trees no longer have to just grow horizontally. Many can instead grow up toward the sky. This takes less energy. And with all that leftover energy, these trees have started producing more seeds. This happens especially in places where white spruce (白云杉) grows.

White spruce, which is a North American tree, is quite able to produce a lot of seeds, which can move long distances in the wind. When windblown seeds end up on the tundra beyond the tree line, they eventually can sprout(发芽) new trees. This explains how a forest can move. Of course, the process would work only if the tundra were warm enough. But in recent years, the whole planet has been warming.

New trees will provide shelters for some snow. Keeping the sun's rays from making the white surface disappear. Instead, the trees absorb the sun's heat. This warms the surrounding air. The extra wrmth encourages even more trees to produce seeds. That further boosts a forest's ability to expand. In addition, more trees will trap more snow, preventing much of it from being blown away. Snow can trap heat in the soil below, which encourages trees to grow. The recent rise of temperatures has helped more trees grow past the tree line. People worry about impacts on the animals that depend on frozen conditions for food and shelter.

【1】What is the main cause of the trees in the Arctic moving northward?

A．The shrinking of northern tundra.

B．The rising temperature.

C．The fierce and cold wind.

D．The abundant resources in the north.

【2】What does the underlined word “this” in Paragraph 2 mean?

A．To produce more seeds.

B．To move northward.

C．To respond to the climate change.

D．To protect themselves from the cold wind.

【3】What can be inferred from the last paragraph?

A．New trees can trap the snow, which may make the soil colder.

B．The trapped snow prevents new trees from producing more seeds.

C．New trees can make the surrounding air warmer.

D．New trees can bring more food and shelter to local animals.

【4】The passage is most probably taken from ________.

A．a science report B．a health report

C．a fashion magazine D．a children's magazine

Answer 1

【答案】

【1】B

【2】D

【3】C

【4】A

【解析】

试题分析：

【1】细节理解题。根据第二段的第二句“Across the Arctic, temperatures are rising faster than anywhere else in the world.”以及本段的整体内容可知，不断上升的气温是北极圈树木北移的主要原因，即B项正确。

【2】代词指代题。根据画线词前的“Trees growing along the tree line must protect themselves from the cold wind.”可知，画线词this 指代的是本句中的“protect themselves from the cold wind”，故D项正确。

【3】推理判断题。根据最后一段中的“New trees will provide shelters for the surrounding air.”可推知，新树会让周围的空气更加温暖，故C项正确。

【4】文章出处题。根据文章的整体内容可推知，本文主要研究的是气候变暖对北极圈植物的影响，故该文应选自科研报告，故A项正确。