A:R1先后两次消耗的电功率之比为3:4
B:滑动变阻器R2的最大阻值为10Ω
C:电源电压为10V
D:R1的阻值为20Ω
____
“优柔寡断者,往往患得患失,踌躇不前;草率从事者,必然懒于思考,轻举妄动。”这是缺乏意志的自制性的表现。( )
—What did you do yesterday?—My brother took two friends of ________ to play chess with us. But I don't know _______ of them.