A. bad signal Quality B. low signal strength C. excessive time advance
A. 为不规则形的小片,多向内卷曲或稍具凹凸 B. 外表面灰褐色至棕褐色,偶有残留柔毛 C. 质坚脆,易碎 D. 断面角质样,有光泽 E. 气微,味涩