Peter Fern was crazy about mountains. Climbing was the 1 of his life. Church towers，seaside cliffs, rock faces, ice mountains，anything “If it is there” , he used to say, “then I want to climb it.”
So the news of his marriage gave me a 2 . I’d never known him to take much interest in 3 . Well，Peter Fern a married man! I couldn't 4 it. I 5 whether his wife would try to stop some of his risky 6 .
She was French perhaps--from that place 7 he usually spent his holidays. Chamonix，wasn’t it? From Chamonix he'd climbed Mount Blanc on his seventeenth birthday, and another one the day after! That was it, then: She was French，from a mountaineering family. No 8 . No other explanation.
A month later I met them 9 in town. Anna surprised me—because she was English. She was a dancer in the 10．
“I have 11 climbed more than sixty steps in my life,” she told me. “Peter has his 12 , and I’ve got mine. No 13 ”. “None at all，”Peter said, smiling. “Where did you spend your 14 ?” I askeD．Somewhere far 15 theatres and mountains，was it? “We had a week's holiday,” Anna said, “I flew to New York to see Dirke Dancers on Broadway. A wonderful 16 !” Peter said, “I didn’t want to 17 the good weather. So I went to Switzerland and climbed the north 18 of the Eiger with Allen Dunlop. Great 19 , the Eiger. Grand place for a honeymoon! I’ll show you the 20 we took one day.”
1． A．purpose B．love C．answer D．even
2． A．joy B．thought C．lesson D．shock
3． A．mountains B．churches C．faces D．girls
4． A．accept B．understand C．bear D．tell
5． A．believed B．knew C．wondered D．realized
6． A．jobs B．words C．adventures D．deeds
7． A．where B．when C．which D．how
8． A．one B．reason C．sign D．doubt
9． A．all B．two C．both D．double
10．A．family B．mountain C．theatre D．holiday
11．A．ever B．even C．never D．almost
12．A．interests B．life C．room D．car
13．A．wonder B．way C．time D．problems
14．A．days B．honeymoon C．childhood D．rest of life
15．A．away B．as C．by D．from
16．A．show B．sight C．scene D．game
17．A．miss B．escape C．break D．forget
18．A．position B．face C．point D．line
19．A．programme B．progress C．fun D．invention
20．A．photographs B．roles C．sports D．pains
的0-1分布，即PX=0=PX=1=
，PY=0=PY=1=
，定义随机变量
求Z的分布；(X，Z)的联合分布；并问X与Z是否独立．
，将其写成矩阵形式，求Z、(X，Z)的分布：
，故X与Z独立．