储罐罐底常用的严密性试验方法有哪些？
参考答案：
真空箱法、氨气渗透剖腹产和充水试漏法。
— I am shocked at the news that many pupils were killed in the terrible traffic accident.
— So am I. Little the safety of the poor children. [ ]
A. did the local government care for
B. the local government cared for
C. did the local government care about
D. the local government cared about
在净价交易的情况下，成交价格与债券的应计利息是相等的。 ( )
