单子叶作物的根系都是属于须根系。
参考答案：对
— Do you know _____?
— She is answering the telephone. [ ]
A. what is Lucy doing
B. what Lucy is doing
C. what does Lucy do
不锈钢管通球试验时，则可采用等于管子内径（）的木球或不锈钢球做通球试验。
A.70%
B.86%
C.90%
D.76%
