实行大企业之间的“强强联合”（） ①最大幅度提高劳动生产率的可靠保证 ②有利于

在参数估计中利用t分布构造置信区间的条件是（）。

A．总体分布需服从正态分布且方差已知

B．总体分布为正态分布，方差未知

C．总体不一定是正态分布但须是大样本

D．总体不一定是正态分布，但需要方差已知

阅读下面的材料，根据要求写一篇不少于800字的文章。（40分）

有一位女士，多年来总是嘲笑对面的女邻居懒惰：“你看她衣服永远都洗不干净，晾着的衣服总是脏的!”一天，一位朋友到她家做客，听见她的嘲笑，就仔细的观察，然后拿起一块抹布，把这位女士家窗玻璃上的污垢擦干净，然后说：“你看看，对面的衣服还脏吗？”

要求选好角度，确定立意，明确文体，自拟标题；不要脱离材料内容及含意的范围作文，不要套作，不得抄袭。

地壳中含量第一的元素与含量第一的金属元素的单质的反应的化学方程式______．

Earl has been employed by Flash Co, for the past 20 years. During that time he has also invested in the company in the form of shares and debentures. Earl owns 5,000 ordinary shares in Flash Co. The shares are of $1 nominal value and are paid up to the extent of 75%. The debentures, to the value of $5,000, are secured by a fixed charge against the land on which Flash Co’s factory is built. In April it was announced that Flash Co was going into immediate insolvent liquidation, owing considerable amounts of money to trade creditors (trade payables). As a result of the suddenness of the decision to liquidate the company, none of the employees received their last month’s wages. In Earl’s case this amounted to $2,000. Required: Advise Earl as to his rights and liabilities in relation to Flash Co in regard to:

(a) his unpaid wages; (3 marks)

据《本地通信线路工程设计规范》，在工程设计中，应采用取得信息产业部电信设备入网证的产品。没有入网合格许可的主要设备、材料（）在工程中使用。