古希腊提出“助产术”的著名思想家是柏拉图。

一个静止的质量为m的不稳定原子核，当它完成一次α衰变，以速度v发射出一个质量为m_α的α粒子后，其剩余部分的速度为 [ ]

A．

B．-v

C．

D．

人工髋关节置换时，髋臼外展角应为

A．40°～50°

B．大于60°

C．小于40°

D．40°～60°

E．30°～40°

回购价格与本金的关系是()。

A．回购价格＝本金

B．回购价格＝本金+利息

C．回购价格＝本金－利息

D．回购价格与本金无关系

请先通读下列短文，然后从所给的七个选项中选出能填入空格的最佳选项。

     1_____ One of the best things you can possibly do is to start you own club. It's great fun especially if you

are the sort of person who feels there's never anything to do during the school holidays. 　　

     The first thing you need to come up with is an idea for your club. What are you interested in? Pets, clothes,

pop music or dancing groups, sports, or making things? 2_____　　　

     Next you need some friends to be in your club with you. 3_____ All you need is three or four other people

who are interested in the same thing as you. 　　　

     4_____ You should all sit down somewhere together with lots of pieces of paper and write down every name

you can think up. That'll keep you busy for ages. 　　

     At your first meeting you should make up a rule book. And the first rule should be no grown-ups or little/big

brothers or sisters! The best clubs are always secret! 　　

     Now you have just about everything you need, except membership cards. These are very important and again

you will spend a lot of time making them. Use a bright thick pen to make a special design. Why not leave some

space for a photo of yourself? 5_____　　　

     So there you are, get clubbing! Once you get started you'll think of loads of more interesting things to do!

A. That's easy. 　　

B. The list is endless. 　　

C. Enjoy your own club! 　　

D. Invite a designer to join you. 　　

E. Winter vacation is just around the corner. 　　

F. Then you need to pick a name for your club. 　　

G. That will make the membership card really look like it.

长输管道首末站设置一定数量的储泊罐用以储油，其目的是（）

A.稳定油田的生产均衡

B.用以满足用户的需求

C.调整管道输量的平稳

D.保证输油生产的消耗