战国时期著名的冶铁中心有( )。 ①邯郸 ②临淄 ③棠溪 ④宛A．①② B

As students, we have classes for early morning till late afternoon．Therefore, take a ten-minute break between class is definitely important, even necessary. Otherwise we may feel both physically or mentally tired. During the ten-minute break we did something to get rid of tiredness．What we need is to have real rest, instead of getting even tired．So don't do anything that will make you too excited．My ten-minute break is always pleased．I usually take some exercise．Sometime I have a free chat with my classmates．When the new class begins, I feel freshly again.

某企业2012年产品销售量的预测值为5万元，实际销售量为6万元，该企业预测的相对误差是()。

A.16.67% 

B.20.00% 

C.22.56% 

D.25.00%

最适于血液常规检验的抗凝剂是____。

探索适合中国国情的社会主义道路从根本上说是（）。

A、实现三大改造

B、推动中国经济建设

C、摆脱苏联模式影响

D、把马列主义原理同中国具体实际结合起来

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