交流电源即（），直流电源包括弧焊发电机和弧焊整流器。
参考答案：弧焊变压器
下列食物中富含维生素的是
A．猪肉
B．米饭
C．水果
D．白糖
____ makes our school proud is _____ more than 80% of the students have been admitted to key universities.
A．What…because
B．What…that
C．That…what
D．That…because
