专用及备用局扇电源变压器的二次侧低压分支开关必须安装（），每天进行一次漏电试验。
参考答案：低压选择性漏电保护
方程2x+3=7的解是______．
—Can you do the work with _______ money and _______ people ?
—I find it difficult to do it like that. [ ]
A. less; fewer
B. fewer; less
C. little; less
D. fewest; least
