桥涵工程施工质量验收标准规定钻孔桩浇筑水下混凝土前应清底，桩底沉渣允许厚度为：摩擦桩不应大于300mm，柱状不应大于（）。
参考答案：100mm
John spent most of his time practising speaking English in addition _____ his spare time. [ ]
A. of
B. to
C. for
D. into
本病例的适宜治法为
A．滋阴降火
B．滋阴润肺，和络止血
C．补肺益脾
D．滋阴益阳
E．补精固血
