在易燃易爆场所不能使用（）类型的工具敲击。 A.木锤 B.橡胶锤 C.铜锤 D.钢锤

铸造支托的宽度约为磨牙颊舌径的（）。

A.1／4

B.1／3

C.1／2

D.2／3

E.3／4

制冷剂管路的（）是制冷量、冷凝温度、蒸发温度、当量总长度、管径、管材的函数。

葛洲坝、三峡等水电站大多建在[ ]

A．地势第一、第二阶梯过度地带

B．地势第二、第三阶梯过度地带

C．地势第一阶梯上

D．地势第三阶梯上

下面关于握手礼的选项哪一项是错误的？（）

A、握手的顺序主要取决于"尊者优先"原则

B、社交场合应由先到者先伸手为礼

C、客人告辞时，应由客人先伸手为礼

D、职位低的人与职位高的人握手时应先伸手为礼

In low-speed network, it is usually adequate to wait for congestion to occur and then react to it by telling the source of packets to slow down. In high-speed networks, this approach often works poorly, because in the (1) between sending the notification and notification arriving at the source, thousands of additional (2) may arrive. In ATM network, a major tool for preventing (3) is (4) control. When a host wants a new virtual (5) ,it must describe the traffic to be offered and the service expected.

2（）

A．packets

B．cells

C．message

D．files