液压系统中只要有顺序阀,一定有顺序动作回路。( )
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集总参数电路代替实际电路的条件是?
A. l《λ
B. l≥λ
C. l=λ
D. l与λ无关
The man __________ for his frankness will make a speech at the meeting.
A. knowing
B. known
C. beingknown
D. having known
There was nothing to prevent her from _______ so.
A. to do
B. doing
C. done
D. being done
He was seen ________out five minutes ago.
A. go
B. to going
C. to go
D. having gone