How can it matter if I leave one little tap running, one little light on or leave a little piece of litter on the road? And anyway, no one will know.” Of course, it wouldn’t matter if there were just a few people in the world. But just think of all the millions of people     1    (say) to themselves: “It doesn’t matter. It’s just me. And, anyway, no one knows.” Millions of gallons of water would     2    (waste); millions of lights would be left on; millions of pieces of litter would be dropped. And all of this would be very     3    (harm).

Owing to global warming, sea levels are rising and rain forests are dying. It’s clear that humans     1    (cause)most of the warming over the past century by releasing greenhouse gases, the levels of which are     2    (high)now than at any time in the past.

Global warming is causing a set of changes to the earth’s climate     3     vary from place to place. Many people think that global warming is the same as climate change. However, scientists use “climate change” when describing the complex shifts now affecting     4    (we)planet’s weather and climate systems—in part because some areas     5    （actual）get cooler in the short term.

Climate change includes not only rising average temperatures but also extreme weather events and a range of other     6    (consequence). All of them are appearing as humans continue to add greenhouse gases to the atmosphere,     7    (change)the rhythms(节奏)of climate that all living things have come to rely     8    .

What shall we do and what can we do     9    (slow) this human-caused warming? How shall we deal with the changes we’ve already set into motion? While we struggle to figure it all out,     10     future of the earth hangs in the balance.

Global warming is a gradual increase in the earth’s temperature, generally due to the greenhouse effect    1    (cause) by increased levels of carbon dioxide and other pollutants.

Temperatures and sea levels are rising, possibly contributing    2    more storms. The rising has influenced a lot,     3    (result)in a lot of climate problems, and humans are at least partially    4    (blame). Global warming causes climate change,    5    places a serious threat to life on the earth in    6    (vary) forms like widespread flooding and extreme weather. Climate experts    7    (gather) detailed observations of different weather    8    (phenomenon) since the mid-20th and of related influences on climate. Scientists have high confidence    9     global temperatures will continue to rise for decades to come,    10    (large)due to greenhouse gases produced by human activities.

Poor environment is connected with poor health. Now a new public-health     1     (tend)is becoming apparent: Making indoor air cleaner.

Let’s take schools for example. Across Denmark, France, and Sweden, researchers found that indoor-air quality in 66% of classrooms fell short     2     healthy standards. Outdoor-air pollution can get inside buildings — childhood     3     (expose)can affect their physical development and academic performance, and cause cancer.

The problem extends well beyond classrooms. Many people spend more than 90% of their time     4     (stay)indoors. Spaces in buildings with poor air may cause a range of diseases — headaches, shortness of breath, coughs and discomfort of eye, nose, throat and skin. Poor air     5     (blame)for decreased productivity in the past few years.

Covid-19 has brought a new urgency to the matter     6     (great). More investment would be well spent. Better indoor air improves academic development — math     7     reading scores go up. Meanwhile pupils are     8     (attentive)in class. Poor air indoors is the     9     (forget)part when people improved public health. Covid-19 should lead policymakers to focus on the problem,     10     is of great importance for people’s well-being.

Many scientists say we are now entering the Earth’s sixth mass extinction.If a sixth mass extinction    1    (occur ),scientists who have studied the issue believe that up to three quarters of all species on Earth could die out Of course, as we humans depend on so many species for our survival, we would also be at risk of    2    ( die) out. Our world and our lives depend on the balance in nature between animals and plants. Without forests, we would have no air to    3    ( breath ),and without clean water we would be unable to survive.

It is reported that at present a city in Japan has a problem with graffiti(涂鸦). However, it is not the usual type of graffiti with paint from spray cans     1    (use) to write on walls. It is graffiti in sand.

Officials in the city of Tottori are asking tourists to give up     2     (write) messages and drawing pictures in the sand of its giant sand dunes (沙丘). The officials say the graffiti causes damage to the dunes,     3     destroys the pleasure others get in looking at the sand.

More than 3,300 cases of "sand graffiti"     4     (occur) at the tourist spot in the past decade. In January, two overseas tourists were ordered     5     (erase) a 25-meter-long message that read "Happy Birthday Natalie".

The Tottori Sand Dunes are famous throughout Japan     6     their natural beauty. They are the largest and longest sand dunes in the country and form part of     7     scenic coastal park on the sea of Japan coast. The biggest dune is 50 meters high.

The local government wants to improve tourists' understanding of the     8     (important) of the dunes. It will set up much     9     (many) signs in English, Chinese and Korean asking people to respect the dunes. A spokesman said, "We are concerned about whether the rules are     10     (complete) understood, and we want to continue to protect views of the beautiful sand dunes."