When it was introduced, most people did not like itas well as "regular" coffee, and it took severalyears to gain general acceptance.The first paragraph tells us that a new product is________.
A. not easily accepted by the public
B. often inferior to old ones at first
C. often more expensive than old ones
D. usually introduced to satisfy different tastes
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Regardless of its power source, the auto in thefuture will still be the main problem in urbantraffic congestion (拥挤).What is the author's main concern?
A. How to render automobiles pollution-free.
B. How to make smaller and safer automobiles.
C. How to solve the problem of traffic jams.
D. How to develop an automated subway system.
增强型NMOS管工作在饱和区的条件是_____。
A. vGS>VTN ,vDS≥(vGS-VTN)
B. vGS>VTN ,vDS≥0
C. vGS>0 ,vDS≥0
D. vGS<0 ,vDS≤0
工作在饱和区的增强型NMOS管_____。
A. iD=Kn(vGS-VTN)2
B. iD=0
C. iD=2Kn(vGS-VTN)
D. iD=gmvGS
增强型PMOS管的开启电压_____。
A. 大于0
B. 等于0
C. 小于0
D. 可大于0也可小于0