【C3】A．cleanedB．washedC．sweptD．brushed

The purpose of the commutator and brushes on a D.Cgenerator is to .

The windows of the room （) once a week.A、has been cleanedB、is cleanedC、are cleanedD、are

共用题干A Doctor in the House Brushing yo

共用题干A Doctor in the House Brushing yo

共用题干A Doctor in the House Brushing yo

共用题干A Doctor in the House Brushing yo