将材料平铺垫板上,右手握刀模,将其放在材料的()位置上。
A.相反
B.正确
C.相近
D.正中
参考答案:B
建造一座厂房,实际投资20万元,正好比计划节省了4万元,节省了百分之几?
My brother often helps my mum _____ the house on Sunday. [ ]
A. cleans
B. to clean
C. cleaning
D. with cleaning