【单选题】Which of the following best explains why a type 3 filter was selected for experiments 2 and 3?
A.
The frequency response varied more widely when filter type 3 was used than when either Filter type 1 or Filter type 2 was used.
B.
Filter type 3 contains a ground and was therefore the safest of the three types of filters to experiment with.
C.
Filter type 3 is the only one among the three that contains an inductor.
D.
Input voltage could be more easily regulated using a type 3 filter than using either a type 1 or type 2 filter.
【单选题】(26〜27题共用题干)男,55岁。慢性乙型肝炎病史15年,乏力,间断下肢水肿5年。腹泻4天,发热、腹胀、尿少3天。查体:全腹压痛,移动性浊音阳性。最可能的诊断是
【单选题】根据《风景名胜区条例》第十四条规定,风景名胜区应当自设立之日起2年内编制完成总体规划。总体规划的规划期一般为( )年。
【单选题】《风景名胜区条例》规定,风景名胜区应当自设立之日起( )年内编制完成总体规划,其规划期一般为20年。
【单选题】When paralleling two alternators using three synchronizing lamps, the flickering of all three lamps becomes progressively slower and slower. This means the _______.
A.
frequency of the incoming generator is approaching that of the bus
B.
frequency of the incoming alternator is less than that of the bus
C.
phase rotation of the incoming alternators is opposite to that of the bus
D.
terminal voltage of the incoming alternator is approaching that of the bus