变压比测量成套仪尽量采用()。
A. 油浸式调压器
B. 自耦式调压器
C. 感应调压器
D. 隔离调压器
Which two statements are true regarding subqueries? ()
A subquery can retrieve zero or more rows
B. Only two subqueries can be placed atone level
C. A subquery can be used only in SQL query statements
D. A subquery can appear on either side of a comparison operator
E. There is no limit on the number of subquery levels in the WHERE clause of a SELECT statement&e
中心控制室接地干线单独设置接地体时,接地电阻不应大于()Ω。
A. 1
B. 4
C. 10
D. 20
示水膏是在测量水高时,将其涂在检水尺上,可清晰显示出油水界面在()上的位置。
A. 油罐
B. 检水尺
C. 量油尺尺带
D. 量油尺尺铊