婴儿阶段（特别是2岁前）游戏的基本特征是（） 社会性。 象征性。 规则性。 感觉运动性。
Which statement is true about mouse events? （） The cursor style can be set to CAUTION. 。 Double-clicking a mouse button can potentially fire six mouse event triggers. 。 The values for the SYSTEM.MOUSE_BUTTON_PRESSED system variable can only be 1 or 2. 。 Click and double-click button actions can only detect if the mouse is positioned in an item.。
大学生社会知觉的共同特征有（） 选择性。 显著性。 投射性。 两极性。
You need to perform an online table redefinition of an existing SALES table to partition it into two tablespaces TBS1 and TBS2. The SALES table has a materialized view， materialized log， indexes， referential integrity constraint， and triggers with the PRECEDES clause existing on it. What action is required for dependent objects when you perform online table redefinition？（） The dependent materialized view should have a complete refresh performed after the online table redefinition process.。 Triggers with the PRECEDES clause should be disabled before the online table redefinition process.。 Referential integrity constraints must be manually enabled after the online table redefinition process.。 The materialized log should be dropped before the online table redefinition process.。
液化石油气的贮罐首次使用或检修后使用要求容器内含氧量不能大于（）%。 8；。 7；。 6；。 3。
被称为19世纪三大科学发现的是（）。（1）细胞学说（2）进化论（3）相对论（4）能量守衡定律
