试水膏在检测中,要求的停留时间是()秒。
A、10~20
B、20~30
C、30~40
D、40~50
参考答案:A
读下面两封信判断正误。
1.Jenny doesn't want to look unfriendly.
2.Waldo agrees with his parents.
3.Jenny feels happy all the time.
4.Jenny used to be heavy.
5.Waldo likes his little brother.
土基的压实是路基施工及其重要的环节,是保证路基质量的关键。在实际操作中,压实度表示某一有限厚度的路面结构经碾压后的()。