RCT
参考答案:
受试者被随机分配到各组的平行对照试验称为随机对照试验。
乘客问询的处理规定是怎样的?
完成句子
①舞台上的歌手们挥手致意,粉丝们也向他们挥手.
The singers on the stage ______________ and the fans ______________.
②我向母亲挥手告别时她哭了.
My mother was crying as I______________to her.
③他招手让我过去.
He ______________ go over tohim.