The internet will open up new vistas (前景),create the global

The internet will open up new vistas (前景),create the global village -- you can make new friends all around the world.That,at least,is what it promised us.The difficulty is that it did not take the human mind into account.The reality is that we cannot keep relationships with more than a limited number of people.No matter how hard the internet tries to put you in communication,its best efforts will be defeated by your mind.
The problem is twofold (双重的).First,there is a limit on the number of people we can hold in mind and have a meaningful relationship with.That number is about 150 and is set by the size of our brain.Second,the quality of your relationships depends on the amount of time you invest (投入) in them.We invest a lot in a small number of people and then distribute what's left among as many others as we can.The problem is that if we invest little time in a person,our engagement with that person will decline (减弱) until eventually it dies into "someone I once knew".
This is not,of course,to say that the internet doesn't serve a socially valuable function.Of course it does.But the question is not that it allows you to increase the size of your social circle to include the rest of the world,but that you can keep your relationships with your existing friends going even though you have to more to the other side of the world.
In one sense,that's a good thing.But it also has a disadvantage.If you continue to invest in your old friends even though you can no longer see then,then certainly you aren't using your time to make new friends where you now live.And I suspect that probably isn't the best use of your time.Meaningful relationships are about being able to communicate with each other,face to face.The internet will slow down the rate with which relationships end,but it won't stop that happening eventually.
74.According to the passenger,the author holds the view that____.
　　A.the internet fails to play so valuable a role in communication as it promised
　　B.the internet determines the quality of social relationships
　　C.the internet greatly increases the size of social circles
　　D.the internet communication is no less effective than the
　　face-to-face talk
　　75.What is the author’s attitude towards the use of the internet to strengthen relationships?
　　A.He is uncertain about it.B.He is hopeful of it.
　　C.He approves of it.D.He doubts it.
74题为什么选A不选C?倒数第二段第三句But the question is not that it allows you to increase the size of your social circle to include the rest of the world 不是应该选C吗?
75题为什么选D不选B?第一段的That,at least,is what it promised us.不就证明他是hopeful吗?

74题：开篇提出That, at least, is what it promised us. The difficulty is that it did not take the human mind into account……这至少是我们曾经预期的结果,但是它没有考虑到人的大脑局限等,所以并不像曾经预期的那样好,C项中,原句But the question is not that it allows you to increase the size of your social circle to include the rest of the world……but that……强调第二个that后面的内容并不能代表整篇文章作者的观点.
75题：这里的at least 表示让步,缓和语气,且用了过去式,表示这只是它过去给我们的希望,前景,它存在困难The difficulty is that …且无论怎么努力,其作用都会因人的大脑而局限（No matter how hard the internet tries to put you in communication, its best efforts will be defeated by your mind）
个人见解,希望能帮到你~
再问： 那75题为什么不能选A呢？
再答： 同上，也想这么说，差别真不大，但doubt直接表示怀疑，质疑（算否定的），而uncertain是不确定，可以是好的，也可以是坏的一面（算中性的），大概如此，表示我尽力了……