在多元线性回归中，已知复相关系数Ryx1x2，则变量Y的变异由变量X1和X2的回归所

肝炎具有传染性，患者传染性最强的阶段是（　　）

A．发病前

B．发病初期表现出症状时

C．发病中期

D．病症最严重的时期

从广义上说，当决策全过程的活动涉及两个或两个以上的人时，不论这些人是一般性地参与决策，还是真正地作出决策，这时的决策都可被称为是群体决策。 ( )

Charles liked music very much when he was at school, but (41) he went to the university he decided to study medicine (42) music. When he passed his examinations and became a doctor, he had to work in a hospital for (43) . There he discovered that a lot of patients were happier if (44) music was played for them. When Charles got an office and began to work (45) himself, he decided to (46) his patients happy by having a tape recorder in his waiting room play beautiful music for them.
But (47) the tape recorder had been put in(安装), Charles’ nurse heard a woman complain in the crowded (48) , "Here we’re (49) waiting to see the doctor, and he’s just playing (50) piano in his office instead of doing his work. \

[A]instead of[B]because of[C]in spite of

因印章损毁、印章规格内容变更等导致临柜业务印章停用、变更的，应在停用（）办理印章停用手续，在相关登记簿上进行登记，并将停用的印章及时上缴。

A.当日

B.次日

C.1周内

D.1月内

配气机构根据气门安装的位置不同，可分为侧置式和（）两种。

A.前置式

B.后置式

C.顶置式

D.左置式