英语四级新闻听力20210813

一、听力练习

1.

A. Air.

D. Water.

C. Ice.

D. Molten.

2.

A. Because of the power issues.

B. Because of blocked signal.

C. Because of explosion.

D. Because of radiation.

二、听力文本

A quake-measuring device on Mars is providing the first close look at the inside of the planet. The findings show a surprisingly thin crust and a hot, molten core beneath the Martian surface. Scientists recently reported that the Martian crust is about the same thickness as Earth's. The Martian mantle, the area between the crust and core, is about half as thick as Earth's. And the Martian core is bigger than what the scientists expected. However, it is still much smaller than Earth's core. These new studies confirm that the Martian core is molten. But scientists say more research is needed to know whether Mars has a solid inner core like Earth's, surrounded by a molten outer core. Current measurements show Mars' crust possibly reaching as deep as 20 kilometers to 37 kilometers. The mantle extends down nearly 1,600 kilometers. And the relatively lightweight core has a radius of 1,830 kilometers. Earth's crust ranges from a few kilometers beneath the oceans to more than 70 kilometers beneath the Himalayan mountains in Asia. Earth is almost double the size of Mars. Flight controllers have increased power by using the spacecraft's robotic arm to release sand into the wind to remove some of the dust on the panels. The seismometer has continued working. But all other science instruments have been temporarily stopped because of the power issues. A German heat-seeking device, however, was declared dead in January after it failed to dig more than half a meter into the planet.

Question 1: According to the news report, what is the state of Martian core?

Question 2: According to the news report, why have all other science instruments except the seismometer have been temporarily stopped?

三、重点词汇

1. molten: fused or liquefied by heat : melted. How to use molten in a sentence 融化的

2. mantle: the part of the earth that is below the surface and that surrounds the smaller part in the center 地幔

四、背景知识

2018年11月26日，美国国家航空航天局（NASA）的“洞察”号火星探测器携带一种被称为“内部结构地震实验”（SEIS）的六传感器地震仪在火星上降落，任务是记录地震波穿过陆地内部结构的过程，从而探索这颗红色星球的地壳、地幔和地核。自“扎根”火星以来，“洞察”号在其着陆点测量了大约733次地震。科学家基于其中35次地震的数据，揭示了火星的内部结构，估计了火星地核的大小、地幔的结构和地壳的厚度。“洞察号”的发现表明，火星有一个巨大的液态核心。它的最外层距离地表约1560公里。火星半径仅为地球半径的1/2左右。来自瑞士苏黎世联邦理工学院的地震学家、研究合著者阿米尔汗称，火星地核的半径为1830公里，“比预期的要大”。而地球核心的半径约为3480公里，这意味着，火星的核心也约为地球核心半径的一半。地核尺寸越大，密度越低。火星具有较大尺寸的核心半径说明，与以镍和铁为主要成分的地球核心不同，火星的核心除了铁和镍，还含有氢和氧等较轻的元素，这些成分起到了降低核心凝固温度的作用。因此，尽管有大量热量散失，火星的核心仍然完全是液态的。（背景知识来自于https://xw.qq.com/cmsid/20210727A02YEM00）

五、参考答案

Question 1: D

Question 2: A