下列为构成物流向量的三个数量特征之一的是（） 流体。 载体。 流向。 流速。
他励电动机具有（），这种特性特别适用于当负载变化时要求转速比较稳定的场合。 软机械特性。 较软机械特性。 很软机械特性。 硬机械特性。
On Jan 11， 2005 at 2：30 P.M.， an erroneous update operation modified all the values of column LASTNAME in the EMPLOYEE table in the Scott schema to an empty string. You are the system administrator， and you want to return the original values in the table. To do so， you decided to flash back the table. Which two options can you use to flash back a table？（） by using Oracle Enterprise Manager。 by issuing the FLASHBACK TABLE statement at the RMAN prompt。 by issuing the FLASHBACK TABLE statement at the SQL prompt。 by issuing the FLASHBACK TABLE statement at the LSNRCTL prompt。
Which statement is true about items that have been assembled into a kit？ （） Only rotating items can be part of a kit.。 Kits can be assembled from lotted items.。 Kits can be assembled from items in different storerooms.。 Items that have been assembled into kits do not appear in item balances.。
李某，23岁。不慎从高处摔下，致呼吸、心跳停止，需立即初期复苏，开放气道的措施应选择（） 仰面抬颈法。 仰面举颊法。 气管插管法。 气管切开法。 仰卧头侧法。
You need to display the last names of those employees who have the letter “A” as the second character in their names.Which SQL statement displays the required results?（）
