China's Worst Sandstorm

China's worst sandstorm in a decade caused mass disruptions on Monday as vast swathes (广大地区) of the country were thrown into a thick, orange haze of dust and sand,     1    (force) authorities to cancel hundreds of flights, shutter roads and schools, and suspend outdoor activities.

In Beijing, poor visibility paralyzed traffic as residents posted photos of skyscrapers seemingly     2     (disappear) into the fog and compared images of the haze to scenes in the dystopian 1982 film Blade Runner.

Beijing and 23 other cities recorded “off the chart”levels of air pollution, according to state media. In Beijing, PM 10, a measure of tiny particles in the air often     3     (associate) with sandstorms, hit more than 9, 000 micrograms per cubic meter, or 180 times the level considered healthy by the World Health Organization. Some residents said they were wearing two masks even while indoors.

Officials in neighboring Mongolia, after the sandstorm     4     (emerge) before sweeping across northern China, were searching for more than 80 herders who had gone missing.

China's National Meteorological Center said it expected 12 provinces and municipalities — an area covering about 160, 000 square miles, about the size of California —     5     (affect) by the storm. The National Health Commission advised residents to stay indoors, seal windows and doors, and to use humidifiers and wet cloth     6     (deal) with any dust.     7     residents must go outside, they should wear a mask, a hat or scarf to protect their face.

California is burning.In recent weeks, hundreds of fires    1    (destroy) structures, torched thousands of acres and blackened the sky with smoke.Fear of the blazes has also led to strategic blackouts that have left millions    2    power.

Fire has always been a part of life California.     3    a series of    4    (factor) have combined to make recent blazes more damaging.Ten of the most destructive fires in the state’s history have happened in the past decade.Things hit new extremes last year with the Camp Fire,     5    caused 85 deaths and burned more than 150,000 acres.

The forces working in concert to spark and spread wildfires pose    6    incredible challenge for California.Climate change is bringing    7     (high) temperatures and more powerful winds that spread the flames.The state’s electrical system is    8     (age), and equipment has been    9     (link) to causing some of the wildfires.There are more than 100 million dead trees in the state’s forests that act    10    material for the blazes.Meanwhile, a statewide housing crisis has pushed more residents to build homes in dangerous fire zones.