On Friday, several photos of the auroras (极光) were posted on social media. These popular images showed red and green auroras above Mohe in Heilongjiang province, located in the northernmost tip of China. Auroras were observed in various regions of northern China, including Heilongjiang, as well as the Inner Mongolia and the Xinjiang Uygur autonomous regions, according to a Saturday news release by the National Center for Space Weather (NCSW). Even in Beijing, a city that rarely sees auroras, clear aurora observations were recorded, it added.

The center noted that the aurora activity was related to recent geomagnetic (地磁的) storms on Earth, saying that due to a solar coronal mass ejection (日冕物质抛射), varying intensities of geomagnetic storms occurred from Friday night to Saturday morning. Along with possibly affecting electricity and telecommunications networks, coronal mass ejections can produce auroras.

Han Dayang, an engineer from the NCSW, said on Sunday that the fundamental cause of geomagnetic storms is solar eruptive activity, specifically coronal mass ejections from the sun. He said on Sina Weibo that under the drive of extremely powerful magnetic-field energy in the active regions of sunspots, the solar surface material is ejected at speeds ranging from hundreds to thousands of kilometers per second, forming a hemispherical (半球形的) shock wave. If the shock wave happens to impact the Earth directly, the high-energy charged particles (粒子) from the sun will cause changes in the direction and magnitude of the Earth’s magnetic field, leading to a geomagnetic storm, he said. Auroras occur as a result of the interaction between these solar particles and the Earth’s magnetic field.

Typically, auroras are more commonly seen in regions closer to the Earth’s magnetic poles, such as the Arctic and Antarctic. In northern China, particularly in Beijing, auroras are relatively rare. But if the geomagnetic storm is exceptionally strong, the range of aurora occurrence can expand.

The NCSW said on Saturday that, based on the latest monitoring, there is still a possibility of small to moderate geomagnetic storms on Monday. That notice has led plenty of Internet users to express their anticipation of witnessing the beauty of the aurora. There are even some people who travel to these places just to catch a glimpse of the aurora.

1.In which of the following cities didn’t people observe auroras?

A Mohe.

B Beijing.

C Hulunbuir.

D Xi’an.

解析：选D。D细节理解题。根据第一段的“These popular images showed red and green auroras above Mohe”“including Heilongjiang, as well as the Inner Mongolia and the Xinjiang Uygur autonomous regions”和“Even in Beijing, a city that rarely sees auroras, clear aurora observations were recorded”可知，受剧烈的太阳活动影响，周五晚，我国黑龙江、新疆、内蒙古、北京等北部地区惊现美丽极光，并未提到北方城市西安。故选D

2.Which question does the third paragraph mainly focus on?

A Are auroras occurring more often?

B Where can you see auroras?

C Why do auroras occur?

D Why are auroras green or red?

解析：选C。C段落大意题。结合本段最后一句“Auroras occur as a result of the interaction between these solar particles and the Earth’s magnetic field.”可知，该段主要描述了极光是怎样产生的。故选C。

3.What does the underlined word “anticipation” mean?

A Expectation.

B Astonishment.

C Disappointment.

D Rejection.

解析：选A。A词义猜测题。根据划线单词后面的“witnessing the beauty of the aurora”和“There are even some people who travel to these places just to catch a glimpse of the aurora.”可知，根据最新监测，周一可能发生小到中等地磁暴，这一通知让许多网友表达了他们对目睹极光之美的期待，很多人甚至跑到这些北方城市只为一睹极光之美。故选A。

4.What is the best title for the passage?

A China’s geomagnetic studies contribute to tackling climate change.

B Electromagnetic storms spur auroras in China’s north.

C Auroras observed in China for 1st time in history.

D Beijing reports surprising sightings of auroras.

解析：选B。B主旨大意题。本文主要描述了地磁暴引发中国北方多地上演“极光秀”的相关情况。故选B。