题目

若随机变量ξ—N(3,22),则η=的期望Eη=_________,Dη=_________. 答案：0  1从方框中选出适当的介词(短语)填空。like; since; for; about; in front of（1）Daming gets up at 6:00 o'clock in the morning. What you?（2）I want to be a doctor my father in the future.（3）There is a long river my house.（4）Amy has learned French many years.（5）Lucy has lived in China five years ago.