根据句意，用所给词的适当形式填空：
小题1:The _______ (postman) wives donated a lot of money to the children in need.
小题2:I found my father still ___________ (wake) when I entered his room at 11 last night.
小题3:The room is too dirty. It requires __________(clean) every day.
小题4:From the __________(happy) on his face, we know that he failed the exam.
小题5:A 5-year-old child is sure to have difficulty __________(explain) such hard problems.
小题6:Do you think _________(achieve) the balance between study and play is possible?
小题7:At present not only the students but also their teacher _____(ask) to come to school on time.
小题8:How __________ (sad) she was telling me that he lost another bike!
小题9:—Kate, didn’t you hear the loud knock at the door?
— Sorry, I _____________( chat ) with my e-friend.
小题10:The book isn’t mine .It belongs to ______ (she)
sin（100πt）（V）的交流电源上，副线圈接有R＝55Ω的负载电阻。原、副线圈匝数之比为2∶1。电流表、电压表均为理想电表。下列说法正确的是 
V 