孔隙率相同、成分相同的材料,具有粗大开口孔隙的较具有细小开口孔隙的吸水率大。()
参考答案:错
—Thank you for joining in our conversation tonight.
—_____.
A.It’s my duty
B.It’s all right
C.It’s my pleasure
D.With pleasure
结实周期性产生的原因