万用表的转换开关是用来选择不同的被测量和不同量限时的切换元件。
参考答案:对
The family have _______ in Yancheng for a week.
A.arrived
B.got
C.been
D.reached
I made a promise to myself _____ this year, my first year in high school, would be different.
A.whether
B.what
C.that
D.how