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问题 单项选择题

能增强心肌兴奋性，又能降低神经肌肉兴奋性的离子是（）

A.K+

B.Na+

C.Ca2+

D.Mg2+

E.Cl

答案

参考答案：C

解析：血浆钙可降低毛细血管和细胞膜的通透性，降低神经、肌肉的兴奋性；骨骼肌中的钙可引起肌肉收缩；血浆钙作为血浆凝血因子参与凝血过程；钙还参与其他重要的生理调节，但不包括pH的调节。

阅读理解
Want to find a job? Now read the following advertisement.
FAIRMONT HOTELK
Five Waiters and Ten Waitresses
-Aged under 22
-At least high school graduate
-Good-looking; men at least
1．72 meters tall and women at least
1．65 meters
-Those knowing foreign languages favoured
-Paid 1, 600-2,200 dollars per month
One Secertary
-Aged under 30
-Female favoured
-Good at writing and skilled at computer
If interested, call 465-4768 or write to:
Mr. Jack Hundris
Room 0825, Fairmont Hotel
567 wood Street, San Markers, 78003
Fax:6954828
WILSON BOOKSTORE
Accountant(会计)
-Aged between 25 and 40
-With an experience of at least two years
With a degree and an accountant certificate(证书)
-Paid 3, 000-4,000 dollars monthly
-With a practical knowledge of computer
Salesclerk
-Basic education of 12 years or more
-Good at computer
-Paid 1, 800-2,2000 dollars monthly
Tel:447-4398
Fax:3485269
小题1:If you don’t know how to use a computer, you can just apply for the position as         .
A．a secretaryB．a waiter or a waitress
C．an accountantD．a salesclerk
小题2:If you want to get the position of accountant in Wilson Bookstore, you have to satisfy the following conditions EXCEPT        .
A．being a womanB．knowing well how to use a computer
C．having been an accountantD．having n accountant certificate
小题3:If you want to try for a job in Fairmont Hotel, you           .
A．have to be a woman and know foreign languages
B．should be a university graduate
C．have to be taller than 1.72 meters
D．should be younger than 30 years old
小题4:From the ads we can conclude that           .
A．you’ll be better paid in Wilson Bookstore than in Fairmont Hotel
B．all the jobs offered require experience
C．the better education you’ve received, the more money you’ll make
D．if you want to be an accountant, you may call 465-4768
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单项选择题

某项目水泥必须消耗量是51500吨，损耗率为3%，则水泥净用量为( )吨。

A．50000

B．48500

C．42000

D．65000
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