Today（今天） is Sunday. The weather is warm and windy. I can wear my shirt（衬衣） and jeans牛仔裤). I fly a kite on the playground. Tom and Jack wear their T-shirt and shorts. They play football. But in Harbin, it's cold. It's snowy. People put on their coat and hats. They can make a snowman(雪人) and skate(滑雪). It’s funny.

It's windy. So I can fly a kite.

如图甲所示，质量为M=0.5kg的木板静止在光滑水平面上，质量为m=1kg的物块以初速度v₀=4m/s滑上木板的左端，物块与木板之间的动摩擦因数为μ=0.2，在物块滑上木板的同时，给木板施加一个水平向右的恒力F．当恒力F取某一值时，物块在木板上相对于木板滑动的路程为s，给木板施加不同大小的恒力F，得到 $\frac{1}{s}-F$ 的关系如图乙所示，其中AB与横轴平行，且AB段的纵坐标为1m^﹣1．将物块视为质点，最大静摩擦力等于滑动摩擦力，重力加速度g=10m/s²．

扩句

①鲜花盛开了。

②小华做操。