A:136π
B:236π
C:132π
D:120
一个数的相反数是2,则这个数是( )
— The weather report says we are expecting another big snow storm tomorrow.
—________ . I planned to go mountain climbing with my classmates.
270×30=( )
①灰尘由于具有惯性,继续保持原来的静止状态;
②一手拿着沾有灰尘的衣服,用另一只手轻轻拍打;
③灰尘与衣服分离落向地面,衣服便干净了;
④衣服受力后运动状态发生改变,由静止运动起来.