如果脉冲重复频率是10KHz，下面哪种多普勒频移可导致混叠 A．2KHz B．3KH

如图6所示电路，R₁与R₂并联，已知电阻R₁＝10，通过R₁的电流I₁＝3A，请你再补充一个条件，求出电阻R₂的大小.

（要求：条件不能重复，数据自定，并写出简要计算过程）.

（1）补充条件____________，计算______________________________________.

（2）补充条件_____________，计算______________________________________.

在横线里填上合适的小数．

6.1＜______＜6.2

可以填______、______、______（写3个）．

第二节（共5小题；每小题2分，满分10分）

根据短文内容，从短文后的选项中选出能填入空白处的最佳选项。选项中有两项为多余选项。

Students will need to use all of their skills in order to understand the reading selections in Reader’s Choice.

71    These selections provide practice on employing different reading skills to get the message of the writer. They also give students practice in four basic reading skills: skimming, scanning, reading for thorough comprehension, and critical reading.

Skimming involves reading quickly through a text to get an overall idea of its contents. This kind of rapid reading is suitable when you are trying to decide if careful reading is desirable or    72  

Like skimming, scanning is also quick reading. However, in this case the search is more    concentrated.    73    When you read to find a particular date, or number you are scanning.

Reading for thorough comprehension is carefully reading in order to understand the total   meaning of the passage. At this level of comprehension the reader is able to summarize the author’s ideas    74   .

Critical reading demands that a reader makes judgments about what he or she reads. This kind of reedit requires posting and answering questions such as “    75   ”, “Do I share the author’s point of view?” and “Am I convinced by the author’s arguments and evidence?

A．Does my own experience support that of the author?

B．Reader’s Choice is one of the most popular magazines in the world.

C．but has not yet made a critical evaluation of those ideas.

D．The book contains many types of selections on a wide variety of topics.E To scan is to read quickly in order to find out specific information.

F. Do I know about the author?

G. when there is no time to read something carefully.

藿香正气散中治霍乱吐泻之要药是（）。

对G^-杆菌脑膜炎肌内注射治疗最可能无效的药物是（）

A.氨苄西林

B.氯霉素

C.头孢曲松

D.链霉素

E.复方SMZ