Want to know some main functions of mobile phone

I don't know the first question. I don't study mobile phone software, and I don't want to post my answers elsewhere. It is better to find it yourself! I only talk about the second level and the third level according to my experience, for reference only.

2. At present, most domestic mobile phones can support background operation, but the disadvantage of domestic mobile phones is that most of them can't look at the space and display comments, while brand-name mobile phones can. It should be better for MOTO to support background operations, because someone has already done so. Anyone who has used MOTO V3 knows that the most incredible thing about this very old machine is that it can be hung in the background. Nokia is not doing very well. Nokia's machine can only run in the background with smart phones, which is S60, but Nokia's Internet access speed is relatively fast! What about Samsung? I suggest you don't buy Samsung. There is no good mobile phone within 3000 yuan. If it's more than 3000 yuan, why buy Samsung? Better buy a good one!

3. What about the cabin? Mainly depends on the appearance, you said the cottage may include parallel imports and cottages. Shanzhai machines are basically brand-name machines in appearance, but the system content is very different and the quality is not very good. Parallel imports refer to machines produced by legal manufacturers of non-brand mobile phones or smuggled from abroad. They have more functions than licensed mobile phones (due to regional and cultural differences) and better quality than cottage mobile phones. However, they have no after-sales service, so there is no place to solve the problem. You have to go to the small repair department. You spent a lot of money on a mobile phone with good functions. Do you feel free to go to the minor repair department for repairs? Therefore, it is better to buy genuine products and spend money on them! Buying licensed goods is also worry-free. You can buy a mobile phone, but there is no licensed one. There are problems at both ends in three days. Aren't you bored?