因公（私）需要单位开具介绍信的，原则上应由本单位（）批准。
A、主要领导
B、分管领导
C、办公室主任
D、部门负责人
参考答案：C
What is the maximum price an investor should be willing to pay (today) for a 10 year annuity that will generate $ 500 per quarter (such payments to be made at the end of each quarter) , given he wants to earn 12 percent, compounded quarterly（）
A. $11300.
B. $11557.
C. $6440.
不需要患者做皮肤过敏试验的药物是( )。
A．阿莫西林
B．青霉胺
C．普鲁卡因青霉素
D．青霉素
E．胰岛素
