光导纤维是由“纤芯”和“包层”两个同心圆柱体组成的，中心部分是纤芯，纤芯以外的部

请在下边的横线上分别填充一个恰当的字，并解释这个字的意思。

①门可罗             意思：                                      

②声名     起        意思：                                         

按我国现行规定，可以向商业银行申请贴现的票据必须是()商业汇票。

A.未到期的已承兑

B.已到期的已承兑 

C.未到期的未承兑

D.已到期的未承兑

I'm lucky to be in this school for my _____________Chinese course.

A．four-month

B．four months

C．four-months

D．four-months'

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.

（71）处填（）。

A．handshaking

B．interconnecting

C．linkage

D．joining

新晴野望

王维
新晴原野旷，极目无氛垢^①。郭门临渡头，村树连溪口。
白水明田外，碧峰出山后。农月无闲人，倾家事南亩。
[注] ①氛垢：尘埃。

第三联上下两句中最精练传神的分别是哪一个字请作简要分析。