A:2010
B:2011
C:2008
D:2009
— These problems are too hard to . Will you give me some advice? — There are many ways. The most important is to have a careful plan.
三个笔筒平均每个笔筒是6枝笔,第1个笔筒里有6枝笔,第2个笔筒里有7枝笔,第3个笔筒里有____枝笔。
俄罗斯地跨亚欧两洲,但历来被公认为欧洲国家,下列理由中不正确的是( )