更多"[单选题]The alternating current freque"的相关试题:
[单项选择]All ______is a continuous supply of electric power.
A. that is needed
B. what is needed
C. which is most important
D. for our needs
[单选题]The primary function of the _______ is to provide the power to turn the propeller.
A.wing
B.cowling
C.engine
D.firewall
[单选题]UPS（Uninterrupted Power Supply），即（ ），是一种含有储能装置，以逆变器为主要元件、稳压稳频输出的电源保护设备，主要用于单台计算机、计算机网络系统或其他电力电子设备提供不间断的电力供应。
A.不间断电源
B.可间断电源
C.可关断电源
D.开关电源
[单项选择]The primary dissimilarity between the youth market in Europe and that in the U.S. is that______.
A. the volume of sales in Europe is more enormous than that in America
B. there are more abundant sorts of goods in Europe than in America
C. the prominent consumers in the youth market in Europe are the working youth
D. the young customers in Europe have comparatively larger purchasing power
[单项选择]What three primary colors do we see
A. Red, white, and blue.
B. Red, green, and yellow.
C. Red, green, violet.
D. Red, green, blu
[单项选择]The primary purpose of the passage is to
A. explain and resolve a controversy among meteorologists
B. present and describe a recently discovered phenomenon
C. suggest and prove a theory on the cause of a phenomenon
D. describe and confirm research findings under question
E. (E) discuss and evaluate the soundness of certain experimental observations
[单项选择]The primary objective of Basic Econometrics is to provide an elementary but an comprehensive introduction to the art and science of econometrics.
A. brief
B. precise
C. simplified
D. extensive
[单项选择]
Usually the primary purpose of textbook writing is to inform. In textbooks, authors wellinformed in a particular subject or discipline identify the terms, facts, and opinions considered essential to an understanding of the field. While authors’ personal interests play a role in what terms or facts are selected and how they are interpreted, the writing bears a primary or central goal which is not to persuade you to see things from the same perspective. In fact, textbook authors frequently give equal time to opposing points of view so that readers can draw their own conclusion.
However, as you turn from your textbooks to the pages of newspapers and magazines, you may encounter writers with other primary goals. Some write to entertain; others write simply to air a personal preference. However, a good portion of the writers you encounter, particularly on the editorial (社论) pages, write in the hope that you will share or at least seriously consider adopting their
A. Textbook writers are usually better informed in their subjects.
B. Textbook writers are more objective than other types of writers.
C. Editorials aim at sharing facts with the readers.
D. All magazine articles have the aim to share opinions with the readers.
[单项选择]For relation R where primary key contains multiple attributes,no non-key attribute should be functionally dependent on a part of the primary key. This relation R is at least in
A. 1NF
B. 2NF
C. 3NF
D. BCNF
[单项选择]The primary aim of some companies' sponsoring the search engines is to______.
A. cash in on their important role as Web guides
B. boost their avenue
C. reverse a series of losses
D. have their sites visited by the Internet users more
[单项选择]The primary objective of Basic Econometric, is to provide an elementary but a comprehensive introduction to the art and science of econometrics.
A. brief
B. precise
C. simplified
D. extensive
[单项选择]In the United States, primary education requires ______ years.
A. five
B. six
C. seven
D. eight
[单项选择]According to the passage, what is the primary difference between Gall's and Flouren' s views
