海南冬春季节,农作物如何做好各项防寒防冻措施?
参考答案:①推广大棚生产;②推广地膜覆盖栽培新技术;③采用套袋保果新技术;④喷施功能型叶面肥,提高抗寒功能。
A.振幅一定为A
B.周期一定为T
C.速度的最大值一定为v
D.开始振动的方向沿y轴向上或向下取决于它离波源的距离
— Whose English-Chinese dictionary is this?
— It's _____ . My parents got it for my sister and me. [ ]
A. hers
B. ours
C. mine
D. theirs