The latest survey           by www.99.com found more than 12 percent of teenagers want to work as

pilots.       [ ]

A. to be carried out          

B. being carried out      

C. carried out                

D. having been carried out

如果将额定电压为200/36v的变压器接入200v的直流电源，则将发生（）现象。

A.输出36V直流电压

B.输出电压低于36V

C.输出6V电压原绕组过热

D.无电压输出，原绕组严重过热而烧坏