More and more public schools in America make it a rule that students must finish a certain amount of community service {#blank#}1{#/blank#} they are allowed to graduate from high school. They work on projects like making the environment better or {#blank#}2{#/blank#} (feed) homeless people.

    Many school systems in the United States now ask students {#blank#}3{#/blank#} (do) some kinds of community service as part of their studies. Students involved in service projects help {#blank#}4{#/blank#} (they) as well as their communities. They learn about the needs of people and aid {#blank#}5{#/blank#} (organize).For this reason, holidays {#blank#}6{#/blank#} (become) the prime period for volunteer work so far. Volunteers get no pay, but experts point out that it is {#blank#}7{#/blank#} excellent opportunity to learn and practice new skills.

    According to the statistics, more than 60% of young Americans have participated {#blank#}8{#/blank#} different kinds of community service, such as cooking for homeless people, or painting old buildings, etc. Some students like to do their volunteer work in {#blank#}9{#/blank#} (centre) parts of America, but the majority of teens prefer to do it in their hometowns. Tom, a 16-year-old middle school student in California, often {#blank#}10{#/blank#} (do) community service in a local hospital. He works 16 hours every week either receiving calls at the information desk, or helping push patients back to their wards (病房).

    China's Chang'e 5 mission {#blank#}1{#/blank#} (successful) delivered samples of moon rocks and dust to Earth on December 17, 2020. It marks {#blank#}2{#/blank#} first time in 44 years that moon rocks have been brought back to our planet.

    The sample capsule landed in Inner Mongolia {#blank#}3{#/blank#} a little after 2:00 a.m. Thursday local time. The drop-off was the ending of a 23-day mission that began on November 23, {#blank#}4{#/blank#} China sent up Chang'e 5 from a site on Hainan Island. The mission's goal was {#blank#}5{#/blank#} (collect) at least four pounds of material and bring it back to Earth.

    The material collected by Chang'e 5 was from a site in the northwest region of the moon's near side. This area was formed more recently, and the rocks here {#blank#}6{#/blank#} (think) to be only about 1.2 billion years old now. That means scientists {#blank#}7{#/blank#}(study) the material could learn more about the {#blank#}8{#/blank#} (evolve) of the moon.

Although Chang'e 5 was a short mission, it was one of {#blank#}9{#/blank#} (complex) projects undertaken by the Chinese space program so far. The country is far from done with the moon—Chang'e 6, {#blank#}10{#/blank#} (it) second lunar sample return, is ready to launch in 2023 or 2024.

Barbara Millicent Roberts, also called Barbie, {#blank#}1{#/blank#} (consider) the most successful toy doll in history. She first {#blank#}2{#/blank#} (appear) in the world of toys about 60 years ago, and has become very popular among little girls.

According to the Mattel Company, {#blank#}3{#/blank#} created Barbie, 90% of all American girls between 3 and 10 have at least one Barbie at home. However, today there are many dolls competing {#blank#}4{#/blank#} Barbie on the market. Bratz dolls, for example, look more like today's pop {#blank#}5{#/blank#} (star) with lots of makeup and miniskirts. Now Bratz is {#blank#}6{#/blank#} great challenge to Barbie, as the company offers various clothing, too.

It seems that Barbie is no longer {#blank#}7{#/blank#} (attract) to older girls. "For younger girls, playing with a Barbie is much fun, but when they get older, they want something more fashionable and modern," says a shop keeper of a toy store in New York. On the international scene, Barbie remains number one. Although Mattel has been selling fewer Barbies in the United States over the past years, sales in other countries have kept {#blank#}8{#/blank#} (rise). It is hard {#blank#}9{#/blank#} (say) how long Barbie will stay on as a celebrity in the world of toy dolls, but {#blank#}10{#/blank#} (undoubted) 60 is not the age to retire.