题干
With these words, Tom went on ________ his homework.
A：do
B：to doing
C：doing
D：does
答案(点此获取答案解析）
C
With these words, Tom went on ________ his homework.
A：do
B：to doing
C：doing
D：does
图1
sin100πt V，降压变压器的副线圈与滑动变阻器组成闭合电路。若将变压器视为理想变压器，当负载R0=11Ω时
