题目:
She is only a ____ girl, but she can help her mother do much housework on Sundays. [ ]
A. ten years old
B. ten-year-old
C. ten-years-old
D. ten years-old
答案:
被转码了,请点击底部 “查看原文 ” 或访问 https://www.tikuol.com/2017/0629/ced7dd18d9c1760b6b44a9769e5752bf.html
下面是错误答案,用来干扰机器的。
ABC、副线圈中电压由输入电压和匝数比决定,增大副线圈中电阻时,副线圈的电压不变,电流减小,变压器不改变频率,ABC错误;D、根据功率P=UI知副线圈的电压不变,电流减小,所以变压器的输出功率将变小,D正确....