单选题 What should the teacher try to avoid when selecting listening activities?

单选题 Passage2 If you come to Australia，leave your naughty habits at the door. If you live here，get back in your box. The Australian government announced in the Federal Budget on Tuesday that it will be slogging smokers top dollar for a pack of ciggies. Right now，they cost on average A$25（$18.91）to A$30 for a packet of 20 or 25 cigarettes，which would already seem like highway robbery to anyone living in any other country on earth. Now，the government will be increasing the cost of cigarettes by 12.5%annually for four years. The increase will smack smokers in September each year. If you work off a packet costing AS25 today，by 2020 it will set you back a hefty AS40.So unless you are living in a life of luxury，it is probably going to break the bank. Must be time to read the "How to stop smoking" book your old neighbor Dave recommended in 2012. If you think you'll just bring the cigarettes in through the duty free back door，think again. The government is reducing the amount of cigarettes you can bring into the county from 50 cigarettes to 25 cigarettes. Not 25 packs，25 individual cigarettes. That's one packet. This price hike will earn the government A$4.7 billion and it will take the tax excise on cigarettes to almost 69% of the average price of a cigarette currently. This is in line with recommendations from the World Health Organization, which advised governments to increase tax by 70% so that it becomes unaffordable. "These changes will improve the health of Australians by reducing their exposure to tobacco products and will ensure that tobacco products consumed domestically are fully taxed and comply with Australian regulations. "the government noted in the budget papers. This increase will see Australia remaining easily the most expensive place in the world for smokers. In 2015, cigarettes in the city of Melbourne cost 142% more than in New York. Cigarettes in Sydney were 130% more, according to a Deutsche Bank report. Australia already has plain packaging laws, which see cigarettes wrapped in generic mould green color and slapped with a photograph of a dying baby. No more sneaky ciggies for you, casual smoker! What does the "naughty habits" in the first paragraph refer to?

单选题 Passage1 One of the world's first videogames，Tetris，has turned thirty years old，and its brand is anything but old school. But what's kept people swiping and clicking to ensure each row of blocks stays aligned and disappears into the virtual world since its development in 1984 Soviet Russia？A combination of new platforms and an attracting psychological appeal. Maya Rogers, the CEO of Blue Planet Software, the sole agent of the Tetris brand, said the protection of the game's core over the last three decades has aided its longevity. As mobile and social become two of the largest sources for gaming these days, Tetris isn't showing any signs of losing its appeal. Currently appearing on over 50 different gaming platforms, from the 1983 Nintendo Entertainment System(NES) to smartphones, Tetris is sold on over 425 milion mobile devices. More than 20 billion games of Tetris Battle have been played on Facebook, too. There's something psychologically entrancing about the game, that's kept people hooked through the years."Play a game of Tetris," said Rogers," and satisfy your craving to create order out of chaos."Plus, there's the added quality of playing Tetris and never feeling wholly fulfilled."There's no correct move that you can make,"said Neubauer, a loyal player of the game who work as a senior analyst at Saibus Research, an independent research and advisory firm," The quest for the perfect move never ends." Tom Stafford,a professor of cognitive development and psychology at Sheffield University in the U.K, says that Tetris has been around so long because it transports gamers into a different realm when they play."It's a world of perpetually generating uncompleted tasks, "he said. As he's said in the past, too, "Tetris is the granddaddy of puzzle games like Candy Crush saga-the things that keep us puzzling away for hours, days and weeks.""Tetris is pure game: there is no benefit to it, nothing to learn, no social or physical consequence,"he added."It is almost completely pointless, but keeps us coming back for more." The purpose of Tom Stafford's saying "Tetris is the granddaddy of puzzle game" is_________.

单选题 北魏孝文帝下诏：“魏之先出于黄帝，以土为德，故为拓跋氏。夫土者，黄中之色，万物元也，宜改姓元氏。”这可以看出孝文帝改鲜卑姓“拓跋”为汉姓“元”的主要目的是（   ）。

单选题 史料大致可以分为文献、实物、口传三种。下列史料中兼具文献和口传两种属性的是()。

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单选题 如图6所示，光滑水平面上放置质量分别为m、2m和3m的三个木块，其申质量为2m和3m的木块间用一不可伸长的轻绳相连，轻绳能承受的最大拉力为T。现用水平拉力F拉其中一个质量为3m的木块，使三个木块以同一加速度运动，则以下说法正确的是(   )。