菜豆根系木栓化程度高，（）的再生能力差，育苗时必须用营养体育苗。
参考答案：根
I don't know how to start a talk with Betty. She can .sit all day long ______ a word.[ ]
A. by
B. with
C. without
D. on
具有凉血止血、清热利尿、清肺胃热功效的药物是（）
A.大蓟
B.小蓟
C.白茅根
D.地榆
E.槐花
