【判断题】设【图片】由上半椭圆周【图片】与直线【图片】及【图片】所围成的闭区域,则在广义极坐标变换【图片】下,【图片】变成【图片】平面上的闭区域【图片】.
【简答题】To start your own business is usually (cheap) ______ than to buy one.
【简答题】According to the author, if you usually focused on your own problems, or complain frequently, you need to ______.
【单选题】Although they usually did their own painting and papering, on this occasion they brought in a firm of ______ decorators.
【判断题】Festive events can be listed as Intangible Cultural Heritage. ( )
【单选题】如图所示,若把弹簧秤倒过来悬挂,在吊环上挂 2N的重物,则弹簧秤的示数( )
【判断题】设【图片】是平面【图片】上由曲线【图片】,【图片】及直线【图片】,【图片】所围成的在第一象限内的闭区域,则在变换【图片】下,【图片】变成平面【图片】上闭区域【图片】.