问题
单项选择题
关于三位四通阀机能图说法正确的是（）。
A.所谓K型，P型，和Y性换向阀，实际是同一种阀，只是四根管子连接不同而已，
B.处于中位时，对于P型和Y型，油泵处于卸荷状态
C.处于中位时，与P型阀相连通往执行机构的两根油管，一起接通油箱.
D.处于中位时，与K型阀相连的执行机构两侧压力相等，并为最大值.
答案
参考答案：A
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关于三位四通阀机能图说法正确的是（）。
A.所谓K型，P型，和Y性换向阀，实际是同一种阀，只是四根管子连接不同而已，
B.处于中位时，对于P型和Y型，油泵处于卸荷状态
C.处于中位时，与P型阀相连通往执行机构的两根油管，一起接通油箱.
D.处于中位时，与K型阀相连的执行机构两侧压力相等，并为最大值.
参考答案：A
| 完形填空。 | |||
Life in 30 years will be 1_ because many changes will take place,but what will the changes be? | |||
| ( )1. A. same ( )2. A. little and little ( )3. A. much ( )4. A. subject ( )5. A. easily ( )6. A. for ( )7. A. build ( )8. A. rooms ( )9. A. done ( )10.A. works enough | B. differenc B. less and less B. many B. subjects B. more easily B. with B. building B. room B. do B. enough works | C. different C. many and many C. more C. way C. easy C. at C. to build C. spaces C. be done C. work enough | D. difficulty D. more and more D. most D. games D. easier D. in D. builds D. sea D. be did D. enough work |