【单选题】Before a Flashback Table operation, you execute the following command: ALTER TABLE employees ENABLE ROW MOVEMENT; Why would you need this to be executed?()
A.
Because row IDs may change during the flashback operation
B.
Because the object number changes after the flashback operation
C.
Because the rows are retrieved from the recycle bin during the flashback operation
D.
Because the table is moved forward and back to a temporary during the flashback operation
【单选题】Before a Flashback Table operation, you execute the following command: ALTER TABLE employees ENABLE ROW MOVEMENT; Why would you need this to be executed?()
A.
Because row IDs may change during the flashback operation
B.
Because the object number changes after the flashback operation
C.
Because the rows are retrieved from the recycle bin during the flashback operation
D.
Because the table is moved forward and back to a temporary during the flashback opertion
【单选题】有关放射性标记物的放射化学纯度的描述,正确的是 ( )
A.
是指结合于抗原上的放射强度占总放射强度的百分率
C.
是指标记抗原结合于抗体的放射强度占总放射强度的百分率
D.
放射化学纯度测定方法是加10倍量抗体和标记抗原反应,测算出B/(B+F)百分率
E.
标记后放射性标记物的分离纯化程度不影响其放射化学纯度
【简答题】Why would you need a computer when you are trying to decide whether or not to build a larger factory or to buy more machines? __________________________________________________________________________...
【多选题】关于卖出看涨期权的说法不正确的有( )。
C.
期权被要求履约风险=执行价格+标的物平仓买入价格-权利金
【单选题】山水田园诗以描写自然风光、农村景物以及安逸恬淡的隐居生活见长,诗境隽永优美,风格恬静淡雅,语言清丽洗练,多用白描手法。 下列不属于山水田园诗的是( )。
A.
岱宗夫如何齐鲁青未了。造化钟神秀,阴阳割昏晓。荡胸生层云,决眦入归鸟。会当凌绝顶,一览众山小
B.
千山鸟飞绝,万径人踪灭。孤舟蓑笠翁,独钓寒江雪
C.
孤山寺北贾亭西,水面初平云脚低。几处早莺争暖树,谁家新燕啄春泥。乱花渐欲迷人眼,浅草才能没马蹄。最爱湖东行不足,绿杨阴里白沙堤
D.
黄河远上白云间,一片孤城万仞山。羌笛何须怨杨柳,春风不度玉门关
【简答题】用K 2 Cr 2 O 7 法测定Fe 2+ 含量的实验中,加入H 3 PO 4 的目的是______,______。
【单选题】描述放射性标记化合物的放射性活度占该样品的总放射性活度的百分比的单位是