英文tense

来源：百度知道 编辑：UC知道 时间：2024/05/17 10:24:38
Since computers were first introduced to the public in the early 1980's, technology (change) has changed a great deal. The first computers (be) were simple machines designed for basic tasks. They (have, not) did not have much memory and they (be, not) <were not> very powerful. Early computers were often quite expensive and customers often (pay) <paid> thousands of dollars for machines which actually (do) <did> very little. Most computers (be) <were> separate, individual machines used mostly as expensive typewriters or for playing games.
为什麼最后3个答案要用过去式.不是现在完成式吗?

一般过去时描述过去的动作,现在完成时则强调过去的动作对现在造成影响.

上文中,

customers often (pay) <paid> thousands of dollars 与 which actually (do) <did> very little, 动作 paid 与 did little 对现在的影响不大,用一般过去时.

Most computers (be) <were> separate, 系表中的 were 也只虽对当时电脑形态的描述,跟现在没有关系,不用强调.

所以以上三处均用一般过去时.

一般过去式是对过去事物的描述，现在完成时强调过去发生的事对现在的影响。

什么答案啊?