②Don't run on the street.
③Don't swim here.
④Don't play football on the street.
⑤Don't smoking.
⑥No fire.
⑦Don't walk this way.
⑧Use the sidewalk, please.
⑨Stop at the red light.
已知在梯形ABCD中,AD∥BC,对角线AC⊥BD,且AC=24,BD=18,那么这个梯形中位线的长等于( )
下列关于一些地理事物的形成原因的说法正确的是( )
计算.
39→+8□→−20□
26→−4□→+15□