【多选题】Exhibit The COMMISSION column shows the monthly commission earned by the employee. Which two tasks would require subqueries or joins in order to be performed in a single step? ()
A.
listing the employees who earn the same amount of commission as employee 3
B.
finding the total commission earned by the employees in department 10
C.
finding the number of employees who earn a commission that is higher than the average commission of the company
D.
listing the departments whose average commission is more that 600
E.
listing the employees who do not earn commission and who are working for department 20 in descending order of the employee ID
F.
listing the employees whose annual commission is more than 6000
【单选题】同轴度要求较高,工序较多的长轴用( )装夹较合适。
【单选题】控制循环锅炉是在______锅炉基础上发展起来的。
【单选题】同轴度要求较高,工序较多的长轴用( )装夹较合适。
【简答题】锅炉发展的第二个方向是在锅筒外部增加受热面,形成 [填空(1)] 系列。A. 水管锅炉
【单选题】Letter “G” shows that“ ()”.
A.
I have a pilot on board
D.
My vessel is healthy .
【单选题】光合作用之谜是经过众多科学家的不懈努力才解开的,以下资料是科学家探究光合作用过程的部分实验,请根据材料回答问题:
1883年,恩吉尔曼把一些好氧并能运动的细菌放入盛有一条丝状绿藻的溶液中并制成装片,放在没有空气和黑暗的环境中,然后用极细的光束照射丝状绿藻,发现细菌只向叶绿体被光照射到的部位集中;再将棱镜产生的连续的不同波长的光投射到丝状绿藻上,发现好氧细菌主要集中在某些光区。维持植物正常生长所需的...