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Musicals, which developed out of the British comedy at the end of the 19th century, are stage productions that use popular-style. songs and dialogs. They put together music and play, as well as song and dance.In Europe, the US and Japan, the musical is a popular form. of performing art. Musicals generally attract more people than do plays or classical music concerts. However, most Chinese people are still not familiar with this form. of art.In 1987, the American musical The Music Man, a heart-warming story about a traveling sales- man who tries to trick a small town into buying his musical instruments, was introduced in China. In 1990, Sunrise was put on stage in Shanghai. It is considered the first Chinese musical in China's history. But neither of these achieved as great a success as had been expected. This makes it clear that in China, musicals are still at their earliest stage of development.By comparison, developed in many Western countries for years, musicals have achieved great success on Broadway (in New York City) as well as in London's West End, both of which are famous for their musicals. The musical has become an important form. of art in these countries.What do we know about musicals in many Western countries? 点击查看答案

Plant GasScientists have been studying natural sources of methane for decades but hadn't regarded plants as a producer, notes Frank Keppler, a geochemist at the Max Planck Institute for Nuclear Physics in Heidelberg, Germany. Now Keppler and his colleagues find that plants, from grasses to trees, may also be sources of the greenhouse gas. This is really surprising, because most scientists assumed that methane production requires an oxygen-free environment.Previously, researchers had thought that it was impossible for plants to make significant mounts of the gas. They had assumed that microbes need to be in environments without oxygen to produce methane. Methane is a greenhouse gas, like carbon dioxide. Gases such as methane and carbon dioxide trap heat in Earth's atmosphere and contribute to global warming.In its experiments, Keppler's team used sealed chambers that contained the same concentration of oxygen that Earth's atmosphere has. They measured the amounts of methane that were released by both living plants and dried plant material, such as fallen leaves.With the dried plants, the researchers took measurement at temperatures ranging from 30 degrees Celsius to 70 degrees C. At 30 degrees C, they found, a gram of dried plant material released up to 3 nanograms of methane per hour. ( One nanogram is a billionth of a gram. ) With every 10-degree rise in temperature, the amount of methane released each hour roughly doubled.Living plants growing at their normal temperatures released as much as 370 nanograms of methane per gram of plant tissue per hour. Methane emissions tripled when living and dead plant was exposed to sunlight.Because there was plenty of oxygen available, it's unlikely that the types of bacteria that normally make methane were involved. Experiments on plants that were grown in water rather than soil also resulted in methane emissions. That's another strong sign that the gas came from the plants and not soil microbes.The new finding is an 'interesting observation,' says Jennifer Y. King, a biogeochemist at the University of Minnesota in St. Paul. Because some types of soil microbes consume methane, they may prevent plant-produced methane from reaching the atmosphere. Field tests will be needed to assess the plant's influence, she notes.What was scientists' understanding of methane? 点击查看答案