"INowadays due to the highly development of internet I can watch a lot moives from computer. But I had to admit that the whole feelings are different between watching flims at home or at cinema."
Ok. So... One thing to consider is that, with all of these tests such as IELTS, FCE etc, they are not only testing you on your English, but also on your ability to answer a question - because answering the question demonstrates that you have understood it properly.
The most important part of this question, is the English verb "to prefer." To prefer = which do you like better?
You have talked, in your answer, about how the internet has changed the way that you watch films. And you have said that it feels different to watch a film at home than at the cinema. But..............
..............What you haven't done is to be clear about which one of the two you like better? Do you like watching films at home better than those at the cinema, or the other way around?