电磁振动给煤机倾角不超过（）。
A、30°
B、20°
C、15°
参考答案：C
The teacher said he needed _____ boys besides his students _____ the classroom.
A．20 other; clean
B．20 more; to clean
C．20 more; cleaning
D．another 20; clean
卵巢癌的治疗原则是
A．手术
B．放疗
C．化疗
D．手术+放疗
E．手术为主的综合治疗
