流量控制阀在系统中依靠改变节流口的通流面积来调节经过阀口的流量，以控制执行元件的
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液压传动系统中的速度控制回路包括、快速运动回路和速度换接回路等。
Researches have _________ to the conclusion that your personality is affected by your genes.
A. come
B. got
C. reached
D. arrived
She kept practicing _________ she could win the National Speaking Competition.
A. to
B. in order to
C. so that
D. because of
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