【单选题】【消耗次数:1】
She has always been quick to pick things up, doing ( ) well in school without really trying.
passably
passable
passenger@passage
参考答案:
复制
纠错
相关题目
【判断题】 What?has she doing?
①  正确
②  错误
【判断题】 Has she been listening? Yes, she has./ No, she hasn’t.
①  正确
②  错误
【单选题】 24. The kind-hearted woman always tries to help others, but recently she has been ____kind and generous.
①  chiefly
②  specially
③  principally
④  especially
【单选题】 I _______ sleep very well, but then I started doing yoga and it really helps.
①  didn’t use to
②  used to
③  was used to
④  wasn’t used to
【单选题】 ____ you know, David has been well lately.
①  Which
②  As
③  What
④  When
【单选题】 She was wondering whether he has been writing anything new ____
①  late
②  later
③  latter
④  lately
【单选题】 It has always been the ___ of our firm to encourage workers to take part in social activities.
①  plan
②  campaign
③  procedure
④  policy
【单选题】 Information has been put forward ___ more middle school graduates will be admitted into universities.
①  while
②  that
③  when
④  as
【单选题】 —Our son has picked up some bad habits recently, and I am really worried about it.— .
①  Yes, they have some bad habits.
②  Cheer up. I believe he will overcome it.
③  Well, he like drawing.
【单选题】 We came finally _________ the conclusion that she has been telling lies all the time.
①  of
②  into
③  to
④  at
随机题目
【判断题】 设随机变量X,Y相互独立,EX=0,EY=1,DX=1,则E[X(X+Y-2)]=0
①  正确
②  错误
【单选题】 设随机变量X在区间[2,4]上服从均匀分布,则P{23}=( )
①  0.5
②  1
③  0
④  0.6
【判断题】 若DX=25,DY=36,<img class=jc-formula data-tex={ \rho }_{XY} src=https://huaweicloudobs.ahjxjy.cn/EAB7249900EB9927E7FE92E488ED7060.png style=white-space: normal; vertical-align: middle;/>=0.4,则D(X+Y)=85.
①  正确
②  错误
【判断题】 假设随机变量X与Y在圆域:<img class=jc-formula data-tex={ x }^{ 2 }+{ y }^{ 2 }\le { r }^{ 2 } src=https://huaweicloudobs.ahjxjy.cn/4E59C7F72A01DDFB5C818DEEB39D61E2.png style=white-space: normal; vertical-align: middle;/>上服从均匀分布,则X与Y不相关。
①  正确
②  错误
【判断题】 设X服从参数为a的泊松分布,且P(X=1)=2P(X=2),则a=2.
①  正确
②  错误
【判断题】 假设随机变量X与Y在圆域:<img class=jc-formula data-tex={ x }^{ 2 }+{ y }^{ 2 }\le { r }^{ 2 } src=https://huaweicloudobs.ahjxjy.cn/4E59C7F72A01DDFB5C818DEEB39D61E2.png style=vertical-align: middle;/>上服从均匀分布,则X与Y的相关系数为0
①  正确
②  错误
【判断题】 设随机变量X,Y同分布,概率密度为<img class=jc-formula data-tex=f(x)=\left\{ 2x{ \theta }^{ 2 },0\frac { 1 }{ \theta } \\ 0,其他 \right src=https://huaweicloudobs.ahjxjy.cn/B860943974FD890BC063E722186E87C7.png style=white-space: normal; vertical-align: middle;/>,若E(CX+2Y)=<img class=jc-formula data-tex=\frac { 1 }{ \theta } src=https://huaweicloudobs.ahjxjy.cn/FCBCB13DE79A1D5DFE5D24FC95A5D1B1.png style=white-space: normal; vertical-align: middle;/>,则C=2.
①  正确
②  错误
【判断题】 假设随机变量X与Y在圆域:<img class=jc-formula data-tex={ x }^{ 2 }+{ y }^{ 2 }\le { r }^{ 2 } src=https://huaweicloudobs.ahjxjy.cn/4E59C7F72A01DDFB5C818DEEB39D61E2.png style=white-space: normal; vertical-align: middle;/>上服从均匀分布,则X与Y是相关的。
①  正确
②  错误
【判断题】 已知X只取-1,1,5,相应的概率为1/(2k),1/(4k),1/(8k)则常数k=7/8.
①  正确
②  错误
【判断题】 假设随机变量X与Y在圆域:<img class=jc-formula data-tex={ x }^{ 2 }+{ y }^{ 2 }\le { r }^{ 2 } src=https://huaweicloudobs.ahjxjy.cn/4E59C7F72A01DDFB5C818DEEB39D61E2.png style=white-space: normal; vertical-align: middle;/>上服从均匀分布,则X与Y不独立。
①  正确
②  错误