若元素a, b, c, d, e, f依次进栈，允许进栈、退栈操作交替进行，但不允许连续三次进行退栈操作， 则不可能得到的出栈序列是（ ）。 A. d, c, e, b, f, a

B. c, b, d, a, e, f

C. b, c, a, e, f, d

D. a, f, e, d, c, b

Jill wants to become a network professional. which certification would be useful for her? a. mcse b. pmp c. comptia a+ d. ccie

Which one of the following is the most accurate definition of technology? a electronic tools that improve functionality b electronic tools that provide entertainment or practical value c any type of tool that serves a practical function d any type of tool that enhances communication

Aobject is used for displaying the results of a question based on stored data. a. query b. report c. table d. form