As an English major student at one of the most famous universities in China, I ply believe that business English is more practical than other fields.

A．a student in English...field

B．a major English student...regions

C．an English major...courses

D．an English student major...sciences

金风科技1.5MW风力发电机组的变流器的1U1是（），2U1和3U1是（），4U1是（）。

A.网侧单元

B.发电机单元

C.制动单元

D.直流单元