在计算技术改造方案的经济效益时，只提高技术装备水平而其产量规模基本不变的技术改造方案

短文改错。

    Tom and Dick are next door neighbor who both work in same office. They often walk together to and

from work. Once they were walking to home together while it suddenly started to rain. Tom quickly opened

his umbrella and said proud, "My wife really has great foresight. She said this morning it would rain and tell

me to carry my umbrella. "Dick smiled and walked up to her under the protection of the umbrella, said, "Mine

has even great foresight. She didn't let me carry one as she knew you'd share yours to me."

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下列关于安全用药的说法中正确的是（   ）

A．俗话说“便宜无好药

B．俗话说“是药三分毒”

C．服药剂量越大，疗效越快

D．久病成医，用药不用看说明

测量设备在购置时要注意设备厂家是否具有：（）

A.计量器具许可证

B.CMC标志

C.产品合格证

D.国家计量行政主管部门认可制造、修理的资质

一个投资项目的净投资额为100000元，平均每年的现金净流量为28000元，若项目期为5年，其回收期为（）。

A、3.4年

B、3.5年

C、3.57年

D、3.6年

产生未焊透的原因是什么？