培育具有鲜明个性和（）的企业精神，最大限度地激发职工内在潜力，是企业文化的首要任务和

一种药品每盒原价10元，两次降价后每盒价格为8.1元，则平均每次降价的百分数为______%．

某植物种群，AA基因型个体占30%，aa基因型个体占20%，则

(1)该植物的A的基因频率是_________。

(2)该植物自交，后代中AA、aa基因型个体分别占__________、__________，这时A的基因频率是_________。

(3)依据现代生物进化理论，这种植物在两年内是否发生了进化？_______原因是__________________。

(4)由此可见，进化的单位是_______，进化的实质是_____________________。

下列图象与对应的叙述相符合的是【  】

A．等质量的铁片、铝片分别与足量且质量分数相同的稀硫酸反应

B．向一定量的H₂SO₄和CuSO₄的混合溶液中滴加NaOH溶液

C．向pH=13的氢氧化钠溶液中不断加水稀释

D．向接近饱和的硝酸钾溶液中加入硝酸钾固体

A local-area network (LAN) is a communications network that (125) a variety of devices and provides a (126) for information exchange among those devices. The scope of the LAN is small typically a single building or a cluster (丛) of buildings. The LAN is usually owned by the same organization that owns the (127) devices. The internal data rate of LAN is at least several Mb/s.

The basic of LAN communication is broadcasting. At each station, there is a transmitter/receiver that communicates over a (128) shared, By other stations. A transmission from any one station is (129) to and received by all other stations.

（127）是（）

A.broadcast

B.cable

C.control

D.interconnects

E.internet

F.meander

G.means

H.medium

I.modem

J.output switch relay

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