设随机变量X服从参数θ=1的指数分布，令函数，，求二维随机变量（Y，Z)的联合分布律．

If I found the book, I______ it to you.

A．will bring

B．would have brought

C．would bring

D．might have brought

I could have done it better if I______ more time.

A．have had

B．had

C．had had

D．will have had

I wish I______ longer this morning, but I had to get up and come to class.

A．could have slept

B．slept

C．might have slept

D．have slept

If I______(be) you, I would have taken part in the party.

I wish I______ longer this morning, but I had to get up and come to class.

A．could have slept

B．slept

C．might have slept

D．have slept

I______ the book. I may well borrow one from the library.

A．need to have bought

B．need have bought

C．needed not bought

D．needn't have bought

My wallet is nowhere to be found. I______ when I was on the bus.

A．must drop it

B．should have dropped it

C．must have dropped it

D．had dropped it

A.would drive rather not

B.would rather not drive

C.would rather drive

D.not would rather drive

I would have written before, but I______ ill.

A．was

B．would been

C．had been

D．were

I'm tired out. I______ all afternoon and I don't seem to have finished anything.

A．shopped

B．have shopped

C．had shopped

D．have been shopping