物流系统化的目的有（）

A、减少客户所需的订货断档

B、保证订货、出货和配送的信息畅通

C、使物流的成本降到最低

D、提高企业的知名度

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.

1（）

A．high

B．low

C．long

D．short