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【简答题】
555定时器构成多谐振荡器时,如果 R 1 =2.2kΩ, R 2 =4.7kΩ,电容C=0.022 μ F, 则该电路的输出频率为 ( ) MHz,占空比为( )%。
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【简答题】II.Choose the best prepositions andadverbs for each sentence. 1. A lot of our new students have a hardtime fitting ______ the group. A. upon B.in to C. about D. down 2. You must...
【单选题】Which of the following can be inferred from the first two paragraphs?
A.
The Internet has become inseparable in people's lives.
B.
The information gained online is not necessarily reliable.
C.
The author is hunting for a well-paid job online.
D.
The employers are not advised to get information about applicants online.
【单选题】Fill in the blanks by selecting suitable words from the word bank. You may not use any of the words more than one. The Internet has made English learning much easier. English leaners used to be ____ t...
A.
tedious
B.
obliged
C.
abundant
D.
beneficial
E.
bulk
F.
adjusted
【单选题】在DGPS中,按照覆盖区域的从小到大的排序为______。919
A.
广域差分GPS、广域增强系统、局域差分GPS
B.
局域差分GPS、广域差分GPS、广域增强系统
C.
广域差分GPS、局域差分GPS、广域增强系统
D.
广域增强系统、广域差分GPS、局域差分GPS
【多选题】“宣讲”除了具有一般演讲的共性特征外,还具有以下哪些特征?
A.
政治性
B.
思想性
C.
目的性
D.
实效性
【判断题】宣讲的本质就是一种演讲,但是,它除了具有一般演讲的共性特征外,还具有鲜明的政治性、思想性、目的性和实效性。
A.
正确
B.
错误
【简答题】There are 1 passages in this part. The passage is followed by some questions or unfinished statements. For each of them there are four choices marked A), B), C) and D). You should decide on the best c...
【简答题】(14分)碱式硫酸铁[Fe(OH)SO 4 ]是一种新型高效絮凝剂,常用于污水处理,在医疗上也可用于治疗消化性溃疡出血。工业上利用废铁屑(含少量氧化铝等)生产碱式硫酸铁的工艺流程如下所示: 部分阳离子以氢氧化物形式沉淀时溶液的pH如表所示: 沉淀物 Fe(OH) 3 Fe(OH) 2 Al(OH) 3 开始沉淀 2.3 7.5 3.4 完全沉淀 3.2 9.7 4.4 请回答下列问题: (1)加入...
【单选题】The Internet has a history of more than ___ years.
A.
sixty
B.
ten
C.
fifty
D.
twenty
【单选题】在DGPS中,按照覆盖区域从小到大的排序为:
A.
广域DGPS、广域增强系统、局域DGPS
B.
局域DGPS、广域DGPS、广域增强系统
C.
广域DGPS、局域DGPS、广域增强系统
D.
广域增强系统、广域DGPS、局域DGPS
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