no darkness for six months of each year and almost no light for the other six months. cf. the Antarctic Circle
tundra: any of the vast, nearly level, treeless plains of the Arctic regions
Paragraph 6
billowing: large swelling mass of billow v.
1. When something made of cloth billows, it swells out and moves slowly in the wind. （布制品）鼓起
The curtains billowed in the breeze... 窗帘在微风中鼓了起来。
Her pink dress billowed out around her. 她粉红色的连衣裙鼓了起来。 ...the billowing sails. 鼓起的风帆 2.
When smoke or cloud billows, it moves slowly upwards or across the sky. （烟或云）翻滚，滚滚向上
...thick plumes of smoke billowing from factory chimneys...
工厂烟囱冒出的滚滚浓烟
Steam billowed out from under the bonnet. 引擎盖下喷出滚滚的蒸汽。 ...billowing clouds of cigarette smoke. 烟雾缭绕 3. n.
A billow of smoke or dust is a large mass of it rising slowly into the air. 腾起的一大团（烟、尘等）
...smoke stacks belching billows of almost solid black smoke. 喷出滚滚黑烟的烟囱
Acre by acre, the rain forest is being burned to create fast pasture for fast-food beef: Bit by bit trees in the rain forest are felled and the land is cleared and turned into pasture where cattle can be raised quickly and slaughtered and the beef can be used in hamburgers.
Pay attention to the connection of the two ―fasts‖ in fast pasture and fast food. With that comes the ―fast‖ disappearance of the rain forest.
the dry season: ant. in the wet season—the rainy season
with more than one Tennessee’s worth of rain forest being slashed and burned each year: the area of rain forest burned in one year is bigger than the state of Tennessee.
worth: equal in area or size slash: cut with a sweeping stroke
If you slash something, you make a long, deep cut in it. e.g. Jack’s face had been slashed with broken glass.
which means we are silencing thousands of songs we have never even heard: Since miles of forest are being destroyed and the habitat for these rare birds no longer exists, thousands of birds which we have not even had a chance to see will become extinct.
Paragraphs 7 & 8
Images that signal the distress of our global environment are now commonly seen almost anywhere: Typical examples showing the dangerous environmental situation in the world can be found almost anywhere.
On some nights, in high northern latitudes, the sky itself offers another ghostly image that signals the loss of ecological balance now in progress: On some nights, in the area at a high northern latitude, the sky alone presents
another example of ill omen showing there is ecological imbalance and this kind of imbalance is developing. latitude (s): an area at particular latitude in high northern latitude在北纬高纬度地区
blot out: hide entirely; obscure
This ―noctilucent cloud‖ …seem quite unnatural
noctilucent cloud: nocti- means night; lucent means shining, translucent designating or of a luminous cloud visible at night
to cloak: to conceal; hide
A fire could have been deliberately started to cloak small coordinated troop movements.可能是有人故意放火掩护小规模的部队协同行动。
The beautiful sweeping coastline was cloaked in mist.美丽的海岸线一望无际，笼罩在迷雾之中。
shimmer: shine with an unsteady light
The lights shimmered on the water.
水面上波光粼粼。
The trees shimmered in the afternoon heat. 午后的热浪中，树木闪着微光。
translucent: partially transparent半透明的
because of a huge buildup of methane gas in the atmosphere: because there has been a big increase of methane gas in the atmosphere methane is released from landfills,…activities:
release: let go; emit
swarm: to move in large numbers
e.g. As the fire spread, people came swarming out of the building.
What should we feel toward these ghosts in the sky: What should our attitude be toward these noctilucent clouds in the sky?
Simple wonder or the mix of emotions we feel at the zoo: Should it only be a feeling of surprise and admiration or a combination of different feelings we experience in the zoo?