下列说法,正确的是 A.所有生物都是由细胞组成的 B.所有细胞都具的细胞膜、细胞

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问题:

下列说法,正确的是

A.所有生物都是由细胞组成的

B.所有细胞都具的细胞膜、细胞质和细胞核

C.所有植物细胞都能进行光合作用

D.细胞是动物和植物的最小结构层次

考点:生物体结构和功能的基本单位细胞中的物质和能量
题型:选择题

明细账既可以根据原始凭证或原始凭证汇总表登记,也可以根据记账凭证登记。

题型:选择题

关于力的概念,下列说法中正确的是(     )

A.力是改变物体运动状态的原因

B.运动物体在其速度方向上必受力

C.大小相同的力的作用一定相同

D.力可以脱离施力物体而存在

题型:选择题

治疗大肠积热型便秘的组穴首选:()

A.中脘、阳陵泉、气海、行间

B.合谷、曲池、腹结、上巨虚

C.脾俞、胃俞、大肠俞、足三里

D.肾俞、关元俞、气海、石关

E.大横、上巨虚、内庭、支沟

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罐笼提升应设置灯光保留信号,以增加提升的安全性。

题型:选择题

A total of 4.6 million digital televisions have been sold, and the sales of HDTV sets have quadrupled since last year. Consumers have bought HDTVs to play their DVDs and to have clearer pictures and wide screens. Only a small percentage of the people who have purchased HDTVs, however, have actually hooked their TVs up to receive high-definition television digital signals. Perhaps television viewers are having trouble keeping up with the changes in technology. Even the manufacturers of HDTVs, like Mitsubishi, Thomson Multimedia, Sony, and Samsung seem to have a tough time learning how to make their sets work with the various digital TV formats because little standardization has been required or implemented in the industry.

Some of the HDTVs weigh over 200 lbs., and a variety of retailers offer a delivery service to the buyer’s home to help install the heavy sets. This is known as a white-glove service and usually comes with an extra fee. After HDTV purchasers get their sets home and hook them up, they will still need to work to get the digital signals to their systems. Most of the industry’s cable providers do not yet offer high~definition programing, and only about 15% of commercial television stations have switched over to even the lowest improved digital pictures. Worse yet, viewers may need to install antenna before they can even get the digital signals to their new HDTV sets. Another frustration for home-theater seekers is that the current HDTV sets allow owners only to watch high-definition programs, not to record them.

On the whole, this passage is positioned to dwell on ().

A. the overall picture of the HDTV sector

B. how the giant TV makers should offer better products

C. a lament over consumers’ inability to use a high-end TV set

D. a criticism of the TV makers for doing nothing about a big problem

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