Light pollution is a serious problem. This became completely obvious when the World Atlas of Artificial Night Sky Brightness, a computer-created map based on thousands of satellite (卫星) photos,     1     (publish) in 2016. The map shows how and where     2    (we) world is lit up at night. Large areas of North America, Europe, and Asia are glowing (发光) with light, while only the most remote (偏远的) places on Earth are in total darkness. Some of the most light-polluted    3     (country) in the world are Singapore, Qatar, and Kuwait.

Sky glow is the brightening of the night sky, mostly over cities, because    4    the electric lights of cars, streetlamps, offices, factories and buildings, turning night into day.

People     5     live in cities with high levels of sky glow have a hard time     6     (see) stars at night. Scientists are     7     (particular) worried about sky glow pollution as it influences their ability     8     (view) space.

According to research, more    9     80% of the world’s population, and 99% of Americans and Europeans, live under sky glow. It sounds pretty, but sky glow    10    (cause) by human activities is one of the most common forms of light pollution.

7 . The traditional school year, with three months of vacation every summer, was first performed when America was an agricultural society and the summer months were needed for farm work. Since then, America has completely changed as a nation. Students no longer spend summers farming, but they aren’t in school, either. The average American student receives 13 weeks off from school each calendar year — with about 11 of those during the summer. Few other countries have more than seven weeks off in a school calendar.

With the U. S. left behind other countries in academics, it’s time to consider year-round schooling. One benefit of this change is that students will not fall victim to the “summer slide,” or the well-documented phenomenon where students forget some of the knowledge they have acquired when too much time is taken off from school. Decades of research shows that it can take from 8 to13 weeks at the beginning of every school year for students to get back to where they were before the summer holiday.

But year-round schooling isn’t just about academics. Teachers and students experience a closer relationship in year-round schools than they do in traditional schools and, in the absence of any long-term break, students do not feel detached from the school environment. These closer bonds and greater attachment pay off. Research shows that students in year-round schools are more self-confident and feel more positive about their schooling experience.

But don’t kids need time to relax? Some childhood development experts believe that time off from school is vital to healthy development as kids are not designed to spend so much of their time inside classrooms and the summer break provides a perfect opportunity to get outside. The problem with this argument is that most children aren’t playing outside or even spending time with other kids. While some children visit summer camps, most stay at home, watching TV or playing games on electronic devices, which hardly benefits them.

The U. S. has changed from a farming economy to a knowledge-and innovation- based economy, so it makes sense for the school year to change as well.

10 . The Best War Novels

The God of that Summer

by Ralf Rothmann

The masterful and painful story is set in Germany. Luisa, a young girl growing up in rural Germany during World War Two, has managed to escape the horrors of city bombing. Unafraid of the realities of life and death, Luisa supports her family until, one day, an incident changes her life forever.

The Librarian of Auschwitz

by Antonio Iturbe

Based on a true story, The Librarian of Auschwitz is about fourteen-year-old Dita. Keeping the libraries’ eight books safe, Dita knows she is putting herself in danger. But she also knows it can help her and her fellow prisoners maintain hope during the darkest of times.

Pippo and Clara

by Diana Rosie

Pippo and Clara are brother and sister. When their mother goes missing one morning, they both go in search of her regardless of the danger of the war. With Clara turning right and Pippo left, the children’s lives are changed forever.

All Quiet on the Western Front

by Erich Maria Remarque

This classic war novel of the First World War is written in the first person by a young German soldier. Paul Bauer is just eighteen and he enters the army with six school friends, each filled with optimistic thoughts. However, they witness such horrors and such severe hardship and suffering that they are unable to even speak about it to anyone but each other.