一般在同类型的阳离子交换树脂或阴离子交换树脂中,弱酸(碱)性阳(阴)离子交换树脂,比强酸(碱)性阳(阴)离子交换树脂的交换容量要大,可是机械强度一般却比较差。()
参考答案:对
His whole school education _____ only 2 years because of his illness.[ ]
A. added up
B. added up to
C. added to
D. was added up to
简述MPS磨煤机的密封空气系统组成及作用?