I’ve listened to the last audio (out of the three you submitted).
I really liked the development of your response:at the beginning you state your opinion clearly and then support it with good reasons and examples. It would be a good idea to add some concusion, for example, you might have said something like ‘for these reasons, I consider the invention of PC one of the greatest technological breakthroughs in history’.
And a few grammar remarks: ‘reasearch’ is uncountable, so make sure you only use it in its singular form (‘do research’). Also, after ‘help’ (in the meaning of ‘make something easier or better’) we use the infinitive form, usually with ‘to’ (‘it help to find’),