题目内容

道岔开通手信号显示方法,旗信号为()。

A. 展开的黄色旗高举头上左右摇动
B. 拢起的黄色旗高举头上左右摇动
C. 展开的黄色旗
D. 黄色旗下压数次

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Mary has a view called EMP_DEPT_LOC_VU that was created based on the EMPLOYEES,DEPARTMENTS, and LOCATIONS tables. She granted SELECT privilege to Scott on this view. Which option enables Scott to eliminate the need to qualify the view with the name MARY .EMP_DEP_LOC_VU each time the view is referenced? ()

A. Scott can create a synonym for the EMP_DEPT_LOC_VU bus using the command: CREATE PRIVATE SYNONYM EDL_VU FOR mary. EMP DEPT_LOC_VU; then he can prefix the columns with this synonymn.
B. Scott can create a synonym for the EMP_DEPT_LOC_VU by using the command: CREATE SYNONYM EDL_VU FOR mary. EMP DEPT_LOC_VU; then he can prefix the columns with this synonym.
C. Scott can create a synonym for the EMP_DEPT_LOC_VU by using the command: CREATE LOCAL SYNONYM EDL_VU FOR mary. EMP DEPT_LOC_VU; then he can prefix the columns with this synonym.
D. Scott cannot create a synonym because synonyms can be created only for tables.
E. Scott cannot create any synonym for Mary's view. Mary should create a private synonym for the view and grant SELECT privilege on that synonym to Scott.

工艺分析时,()不属于零件毛胚工艺性分析内容。

A. 机械性能
B. 加工余量
C. 表面状态
D. 工序尺寸及其公差

当过量空气系数不变时,锅炉负荷变化,锅炉效率也随之变化。在经济负荷以下,锅炉负荷增加,锅炉效率()。

A. 不变
B. 降低
C. 提高

某工程项目合同工期为18个月。施工合同签订以后,施工单位编制了一份初始网络计划,由于该工程施工工艺的要求。计划中工作C、工作H和工作J需共用一台起重施工机械,为此需要对初始网络计划做调整。如果各项工作均按最早开始时间安排,起重机械在现场闲置多长时间?为减少机械闲置,工作C应如何安排?

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