流砂现象
参考答案:
当基坑挖土到达地下水位以下,而土质是细砂或粉砂时,且采用集水坑降水法时,在一定动水压力作用下,坑底下的土就会形成流动状态,随地下水一起流动涌进坑内的现象。
What would be the impact on a firm’ s return on assets ratio (ROA) of the following independent transactions, assuming ROA is less than one Transaction 1: A firm owned investment securities that were classified as available-for-sale and there was a recent decrease in the fair value of these securities. Transaction 2: A firm owned investment securities that were classified as available-for-trading and there was recent increase in the fair value of the securities. Transaction 1 Transaction 2()① Higher Lower ② Higher Higher ③ Lower Higher
A. ①
B. ②
C. ③
大型养路机械用铸铁闸瓦的最大磨耗量为()。
A.15mm
B.20mm
C.25mm