发绀伴杵状指主要见于（） A.发绀型先心病 B.中毒 C.急性心力衰竭 D.肺水肿

复发性阿弗他溃疡（）

A.病因不明

B.病毒感染

C.苍白螺旋体感染

D.局部刺激

E.真菌感染

The following questions present a sentence, part of which or all of which is underlined. Beneath the sentence, you will find five ways of phrasing the underlined part. The first of these repeats the original; the other four are different. If you think the original is best, choose the first answer; otherwise choose one of the others.

These questions test correctness and effectiveness of expression. In choosing your answer, follow the requirements of standard written English; that is, pay attention to grammar, choice of words, and sentence construction. Choose the answer that produces the most effective sentence; this answer should be clear and exact, without awkwardness, ambiguity, redundancy, or grammatical error.

Archeological excavations of Roman ruins on the Greek island of Crete show that securing control over the maritime trade routes of the Eastern Mediterranean was a primary goal of the Romans, as it was of the Greeks in preceding centuries.（）

A. as it was of the Greeks

B. like that of the Greeks

C. as that of the Greeks

D. just as the Greeks did

E. as did the Greeks

已知某高速缓存(Cache采用组相联映像方式，即组问直接映像，组内全相联映像。假设主存容量为4096块，每块256字节，高速缓存包含32块，分8组，每组4块。高速缓存的地址变换表应包含 (28) 个存储单元；每个存储单元应能存放 (29) 位二进制数；每次参与相联比较的是 (30) 个存储单元。

A．8

B．16

C．32

D．48

细菌分子中的质粒是一种（）。

A．线形双链DNA

B．环状单链DNA

C．环状双链DNA

D．环状双链RNA

E．逆转录DNA

光纤直放站的有哪些应用场合：（）

A.有现成光纤资源的区域

B.无线方式衰耗太大的区域

C.长距离链状覆盖区域

D.高话务量需要多载频的区域