题型:阅读理解 题类:常考题 难易度:普通
黑龙江省双鸭山市第一中学2020届高三上学期英语12月月考试卷
City trees grow faster and die younger than trees in rural forestry, a new study finds. Over their lifetimes, then, urban trees will likely absorb less CO2 from the air thah forest trees.
As we all know, the earth would be freezing or burning hot without CO2. However, CO2 is a greenhouse gas, meaning it traps energy from the sun as/heat. That makes temperatures near the ground rise. Human activities, especially the widespread burning-of fossil(化石)fuels, have been sending extra greenhouse gases into the air. This has led to a rise in average temperatures across the globe.
Studies had shown forests readily absorb CO2, but there hadn't been much data on whether city trees grow, die and absorb CO2 at the same rate as forest trees do. So some researchers decided to find out.
To figure out how quickly trees were growing, researchers tracked their diameters (the width of their trunks) between 2005 and 2014. A tree's diameter increases as it grows, just as a person's waist size increases as they gain weight. About half the weight of a tree is carbon, research has shown. Most of the rest is water. Over the nine years' tracking, the researchers found city trees absorbed four times as much carbon from the air as forest trees. However, they were twice as likely to die. So over the lifetime of each type of tree, forest trees actually absorbed more CO2.
City trees grew faster because they had less competition for light from their neighbors. In a forest, trees tend to grow close together, shading their neighbors. Street trees also benefit from higher levels of nitrogen (氮)in rainwater. Nitrogen helps plants grow. Waste gases from gas-burning cars also contain nitrogen, thus enriching city air with nitrogen. Later, rainwater may wash much of it to the ground. Some street trees may also have better access to water than trees in the country because the underground water pipes can leak.
July is a month of fun-filled activities for kids and teens as long as you know where to find them. When you want some fun activities for July, consider these ideas happening in this month.
Secret of the Dragon Time Monday, July 1, 2017, 10:30 a.m. Cost Adult:$7.40 Children(under15): half Booking Phone the booking office:34032578 Address Brisbane Botanic Gardens Note Secret of the Dragon is a magical story about 2 children who are taken on a dragon ride to explore the universe. |
The Search for life: Are We Alone? Time Thursday, July 4, 2017, 2:00 p.m. Cost Adult:$14.50 Children(under15): $8.70 Booking Phone the booking office:34037689 Address Brisbane Botanic Gardens Note Are we truly alone in space? Is there any life out there? These are the questions asked in this show. |
Magic Class Time Friday, July 12, 2017, 10:00 a.m. Cost Free Booking Please call 34038470 to book your Place. Address Centenary Community hub, 171 Dandenong Rd Note Would you like to be a magician? Then join David, the magician, to learn about real magic with playing cards, coins, ring ropes and DIY projects and be able to become the life of the party. |
Science with Me: Making your own guitar Time Saturday, July 20, 2017, 3:00 p.m. Cost Free Booking Please call 34031226 to book your Place. Address 10, Egginton Close Note Do you want to make a guitar with Katy and her mum? Science with Me is going to be with you. Please remember to bring a piece of wood, a hammer, some rubber bands and some nails with you. |
Inspiring young minds!
TOKNOW Magazine is a big hit in the world of children's publishing, bringing a unique combination of challenging ideas and good fun to young fans every month.
What is so special about TOKNOW magazine? Well, it has no ads or promotions inside—instead it is jam-packed with serious ideas. TOKNOW makes complex ideas attractive and accessible to children, who can become involved in advanced concepts and even philosophy(哲学)—and they will soon discover that TOKNOW feels more like a club than just a magazine. |
What's inside? Every month the magazine introduces a fresh new topic with articles, experiments and creative things to make — the magazine also explores philosophy and wellbeing to make sure young readers have a balanced take on life. |
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Take a look online—evidence shows that thousands of teachers and parents know a good thing when they see it and recommend TOKNOW to their friends.
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