3×6=18表示把18平均分成6份,每份是3.
某几何体的三视图如图所示,则该几何体的体积为( )
What is Jane doing?
(Ⅰ)求证:MD=ME;
(Ⅱ)如图2,连OD,OE,当∠C=30°时,求证:四边形ODME是菱形.
My brother usually _____ in a townhouse with us. But now he _____ for an apartment near the school.
《物质构成的奥秘》告诉我们:元素的种类、化学性质分别与下列粒子数密切相关,下列选项正确的是( )