This is ________ book I borrowed yesterday. Isn't it ________ interesting one?
阻值为3Ω与6Ω的电阻,将它们串联,其总电阻为R1;将它们并联,其总电阻为R2,则R1∶R2等于()
矿区某校开展生活中处处有语文的“漫游语文世界”综合性实践活动。请你帮助完成以下活动内容。