如图所示,水平地面上一质地均匀的方形木板在力F1的作用下处于静止状态,若把它看作一个以O点为支点的杠杆,请你画出阻力F2及动力F1的力臂l1.
环抱我国首都—北京的省级行政区域是( )
发源于南亚的宗教是( )
读“我国一月份平均气温分布图”,回答下列各题.
— Who is singing in the next room?
— It be Lucy. She likes singing at this time.
函数y=f(x)的图象在点M(1,f(1))处的切线方程是y=3x﹣2,则f(1)+f′(1)=____