下列有关门诊手术麻醉的说法，正确的是（）

A．为防止患者紧张，强调镇静剂的使用

B．麻醉前常规应用阿托品

C．通常需用麻醉性镇痛药

D．常规禁水

E．麻醉前用药以肌注或静脉为宜

In the following essay, each blank has four choices. Choose the best answer and write down on the answer sheet.

Microwave communication uses (1) -frequency radio waves that travel in straightline sthrough the air. Because the waves cannot (2) with the curvature of the earth, they can be (3) only over short distance. Thus, microwave is a good (4) for sending data between buildings in a city or on a large college campus. For longer distances, the waves must be relayed by means of" dishes" or (5) . These can be installed on towers, highbuildings, and mountain tops.

4（）

A．material

B．equipment

C．medium

D．channel