下列不属于刺激性气体的是（）。
A.一氧化碳
B.氯气
C.二氧化氮
D.氨
参考答案：A
手工清洗医疗器械的水温要求为（）
A.1～5℃
B.5～10℃
C.15～30℃
D.40～60℃
E.70～80℃
Which of the following statements concerning arbitrage-free bond prices is FALSE（）
A. The riskier the bond, the greater is its credit spread.
B. It is not possible to strip coupons from U. S. Treasuries and resell them.
C. The determination of spot rates is usually done using risk-free securities.
