液压起重机液压管路的安全装置，最普遍采用的是装设（）。
A、单向阀
B、平衡阀
C、安全阀
参考答案：C
下列不属于预算外资金的有( )。
A．社会保障基金
B．国有企业税后留有资金
C．乡自筹、统筹资金
D．以政府信誉形成的具有特定用途的基金
The cash conversion cycle is the:（）
A. sum of the time it takes to sell inventory and the time it takes to collect accounts receivable.
B. length of time it takes the firm to pay the credit extended to it for purchases.
C. sum of the time it takes to sell inventory and collect on accounts receivable, less the time it takes to pay for credit purchases.
