In data communication, data link is those parts of two data terminal equipments that are controlled by a protocol along with the (71) data circuit, which together enable data (72) . So-called protocol means, in short, a set of rules that determines the behavior of functional units in achieving communication.

Data circuit, however, consists of a pair of (73) transmission channels that provides a means of two-way data transmission. Between data switching exchanges, the data circuit may or may not include data circuit-terminating equipment (DCE), depending on the type of (74) used at the data switching exchange. Between a data station and a data switching exchange or data concentrator, the data circuit includes the DCE at the data station end, and may include equipment (75) to a DCE at the data switching exchange or dam concentrator location.

（74）处填（）。

A．interface

B．port

C．window

D．entrance

烧伤早期处理正确的是( )

A．烧伤后立即冷敷、治疗

B．碱烧伤后立即以中和剂冲洗

C．烧伤后，创面以凡士林覆盖转运

D．清创时，必须完全清除污物，包括陷入创面内的煤渣等

E．氢氟酸烧伤后，注射钙剂或镁剂，局部封闭