Why do different people like different colors? The answer depends largely     1    cultural values. To the Egyptians, green is a colour     2     stands for the hope and joy of spring. Red is a symbol of good luck in many cultures. During the Spring Festival in China, children     3     (give) money in a red envelope to welcome good fortune in the New Year. For many nations, blue is a symbol of protection and religious beliefs. Greek people often wear a blue necklace, hoping to protect     4     (they) against evils.

People’s     5     (choose) of colors is also affected by their bodies’ reactions to the colors. Green is said to be the most restful colour. It has     6     ability to reduce pain and relax people both mentally and physically. When     7     (work) in a green environment, people have fewer stomachaches. Red     8     (make) a person’s blood pressure rise and increases people’s appetite. Many decorators will include different shades of red in the restaurant. And many commercial websites will have a red “Buy Now” button because red is a colour that     9     (easy) catches a person’s eye. Unlike red, blue is believed to cause people     10     (lose) appetite. Therefore, if you want to eat less, eating from blue plates can help.

From November 1st, 2020, people were knocking on doors across the country     1     (collect) personal information. This is for the     2     (seven) national population census (人口普查).     3     (normal), the Chinese population census takes place every 10 years. It gathers data     4     (include) name, age, ID number, gender, education, marital status, housing situation, etc.

This time, about 7,000,000 staff visited homes for registration work. A new method — online information registration was also used during this census.     5     (compare) with previous surveys, the new method was more     6     (convenience) for those people not living     7     they were officially registered, and those who did not want to be bothered by census takers’ door-to-door surveys. The findings     8     (expect) to give a full picture of the population — its size, structure, distribution and recent changes.

The census’ provides support for     9     (make) national development policies and it has a large impact on our lives. For instance, areas with a higher number of children may receive more funding for public schools. The results can be used to investigate population trends in different cities. The census can help find out     10     number of foreigners living in China and can also tell how many Chinese people have moved to other countries.

The oldest and most common source of renewable energy     1    (know) to man, biomass (有机燃料) is one of the most important forms of energy production in the United States and elsewhere. Since such     2     wide variety of biomass materials is everywhere — from trees and grasses to agricultural and city-life wastes — biomass     3    (promise) to play a continuing role in providing power and heat for millions of people around the world.

According to the Union of Concerned Scientists（UCS), biomass is a kind of renewable energy source     4     produces no carbon dioxide (二氧化碳), because the energy it contains comes from the sun. When plant matter     5    （burn), it gives off the sun’s energy. In this way, biomass serves     6     a sort of natural battery (电池)for storing the sun’s energy. As long as biomass is produced     7    (continue) — with only as much grown as is used — the “battery” lasts forever.

According to the Energy Information Administration, biomass     8    (be) one of the leading renewable energy sources in the United States for several years running through 2007,     9    (make) up between 0.5and 0.9 percent of the nation’s total electricity supply. In 2008 — although the numbers aren’t all in yet — wind power probably took over first place because of the rapid     10    (develop) of wind farms across the country.