从古猿到人的过渡中，最关键的变化是（）。 A．使用工具的改变 B．居住环境的改变

主管税务机关应在纳税人辅导期结束后的30日内，一次性退还纳税人因增购专用发票发生的预缴增值税余额。 ( )

根据花的结构图回答下列问题：

（1）图中[8]______和[9]______是花的主要结构．其中[______]______将来发育成果实，它内部的______将来发育成种子．

（2）图中[3]的名称是______，其内含有______．

（3）花药中的花粉落到雌蕊的柱头上的过程叫做______．

（4）卵细胞和精子结合形成受精卵的过程叫做______．

In a normal recession, the to-do list is clear. Copies of Keynes are dusted off, the banks lower interest rates, the president and Congress cut taxes and hike spending. In time, purchasing, production and loans perk up, and Keynes is placed back on the shelf. No larger alterations to the economy are made, because our economy, but for the occasional bump in the road, is fundamentally sound. This has been the drill in every recession since World War Ⅱ. Republicans and Democrats argue over whose taxes should be cut the most and which projects should be funded, but under public pressure to do something, they usually find some mutually acceptable midpoint and enact a stimulus package. This time, though, don’t expect that to be the end of the story — because the coming recession will not be normal, and our economy is not fundamentally sound. This time around, the nation will have to craft new versions of some of the reforms that Franklin Roosevelt created to steer the nation out of the Great Depression.

分布筋

缩合聚合是吸热反应，但由于温度过高，也会导致系统的压力增加，甚至引起爆裂，泄漏出易燃易爆的单体。