照片影像仅在某一部分出现模糊，原因可能是（）
A.摄影时间过长
B.摄影时暗盒移动
C.摄影时肢体移动
D.屏/片接触不良
E.摄影时球管震动
参考答案：D
消防水带按照内口径分，可分为（）。
A.25mm
B.30mm
C.50mm
D.65mm
E.100mm
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.
