A. 正确 B. 错误
A. 沙质河床0.1~0.3m,石质河床0.2~0.5m B. 沙质河床0.2~0.3m,石质河床0.2~0.5m C. 沙质河床0.1~0.3m,石质河床0.3~0.5m D. 沙质河床0.2~0.3m,石质河床0.3~0.5m