1 . Have you ever stopped to consider how empty the world would look without trees? Below are five of the top benefits that trees provide.

    1     When adults who are feeling down spend time in the forest, they feel better. Forest therapy can range from simply walking among the trees for a couple of hours to meditating (冥想) in a forest. The adults note they become more confident and their mood improves after forest therapy.

Trees help you heal faster. Natural environments, including forests, help you reach a more positive state of mind.     2     In fact, sick people with exposure to nature heal faster than those who don’t, even if it’s just a view through a window!

Trees reduce air pollution and improve respiratory (呼吸的) health. Trees take in many harmful pollutants from our environment.     3    These forests reduce an estimated 670, 000 cases of respiratory illness and save 850 lives.

Trees provide oxygen. Trees are like the lungs of our Earth. They supply us with oxygen while taking away our carbon dioxide and ask for nothing in return. A single tree can provide enough oxygen for four people.     4    

Trees cool cities. Trees cool things down by offering shade and through evapotranspiration (蒸腾作用).     5     Trees even save your money on your electric bill. When a tree offers direct shade for your home, you’ll use less air conditioning.

A．Trees cheer you up!

B．Trees help reduce the effects of climate change.

C．This, in turn, affects your overall state of wellness.

D．In fact, large forests can influence regional weather patterns.

E．So plant more trees around your home if you want to feel cooler.

F．And of course, trees also provide plenty of oxygen for birds and other wildlife.

G．For example, in the US, forests remove 17.4 million tons of pollution per year.

2 . 阅读下面材料，在空白处填入适当的内容（1个单词）或括号内单词的正确形式。

A new study reveals that plants have their own “ bedtime alarm clock ” that helps them survive the night. Researchers at the University of York have discovered that plants possess an internal signal which they believe tells them     1     amount of sugar they have in their systems at dusk. Plants use sunlight to make     2     ( they ) own sugars from photosynthesis (光合作用）during the day and store them to provide energy during the night.

Plants’ ability to predict sunrise and estimate the     3     ( long ) of the night, as well as adjust metabolism (新陈代谢),     4     ( depend ) on a biological time-keeper called a circadian clock. This is a network of genes which drives rhythms of     5     ( rough ) 24 hours. Biologists think it is this signal, or so-called “ alarm ” ,     6     gives plants the information they need to adjust their metabolism in the dark nighttime hours to stay alive.

The researchers discovered a set of genes     7     ( regulate ) by the chemical compound superoxide, which     8     ( associate ) with metabolic activity. And they found by stopping the production of superoxide, they also stopped the effect of sugar     9     these circadian clock genes in the evening,     10     ( reveal ) the plants’ so-called “ alarm ” .

3 . Directions: After reading the passages below, fill in the blanks to make the passages coherent and grammatically correct.For the blanks with a given word, fill in each blank with the proper form of the given word; for the other words, use one word the best fits each blank.

Cactuses are a kind of juicy plants     1     leaves are reduced to spines(针刺).There are no different branches, leaves and stem area.Instead, the whole body     2     (cover) with spines which are reduced leaves.

Whole fleshy area of the plant is doing the work of photosynthesis(光合作用), in which green plants take in water and carbon dioxide(CO2) and produce their own food     3     the help of sunlight.Cactuses have spines on their stems, which can stop the water in it from     4     (evaporate使蒸发).It has a very good root system to take in water from the underground.It stores water in its body.

In some times of the year, cactuses have flowers and even fruits.However, their flowers usually last only for a few days to a few weeks.These days cactuses become very popular and are used widely    5     ornamental（装饰的）plants in houses and offices etc for their beauty.They are also main food of animals     6     (live) in deserts as cactuses contain water important for their survival.What’s more, they can also be made into delicious dishes or foods at table.     7     , cactuses have been spread almost everywhere all around the world.

These are more than 4000 different varieties of cactuses     8     (find) all over the world.They are quite different     9     their sizes, colors and shapes.The Asian biggest cactus garden lies in Panchkula, sector 5 in north India.It is a very big cactus garden and there are hundreds of varieties of cactuses over there.In some varieties, leaves are present but in very reduced form.The American biggest cactus garden lies in Mexico,     10     some species can grow up to 15-20 feet tall like big trees.