The whole concept of bitcoin is focusing on decentralization, meaning there is no middle men to record your identity in your transactions, bitcoin provides anonymity of each users, cracking it down is very impossible.   The possible way for them to know is  if you use a local wallet to transfer or transact money within your country.  If you withdraw using that wallet or withdraw using banks and local establishments, that would be the time government can trace you.  The best way, I think to keep your Bitcoin from the government   is do not advertise your Bitcoin.

It all depends on how careful you have been. For example, ever registered with exchanges, linked addresses for on there, provided proof of who you are, ever done kyc for airdrops, bounties etc

From what I comprehend, the legislature will have the capacity to follow the exchange with BTC that you made when you cashout it on an installment handling foundation/organization in your nation. They'll have the capacity to do that on the grounds that a large portion of these organizations expect you to give KYC records before letting you cashout your cash from them. This will be the main thing that I can consider where they'll have the capacity to interface your name to any BTC exchange.

yes its true that it only happen if the exchange have the KYC for all costumer and the government use that for see who is the holder of bitcoin, buy unfortunately if the country banned bitcoin in that country I think it will banned all exchanger that already exists in that country too right?

They can discover your bitcoin if they look the data of your exchange. Usually exchanges require KYC and you must submit your identity.
The exchange will have your information, and could give it to them if it legally require by them. Your exchange address will have a record to your personal address if you used it to do transactions.

The government has no way to track your BTC usage because no one in this world has ever known whether or not you own it. Unless you decide to show off your identity.

Yes that's right! Bitcoin is anonymous. You will not get track unless on the way how you do receive your exchange. Here in my country, if you're going to use your bank account, and you declared in your bank that you are receiving money only for your businesses and you are receiving very huge money  which is seems inpossible to earn it for a couple of months lets say 3 to 6 months with a very huge amount. And you are earning it regularly like what we know how we earn in doing bitcoin. Plus, you are part of government employees wherein we have statement of assets and liabilities every year and your declaration in your sources of income is so impossible with the amont you have in your bank account then you will be track at all. But if your going to receive your exchanges through other channels then it's anonymous.

Bitcoin transactions are not anonymous. Many people think that they can use Bitcoin for any illegal activity and they will not get caught. If you want to avoid this, you could use Monero which is far more anonymous than Bitcoin or use Bitcoin mixing services which for a small fee will do the work for you. It's good if you don't want to use any other altcoin. Governments have tools which help them to track your transaction.

Bitcoin is anonymous, so the government can't trace you, if you don't do silly things. That's why, bitcoin is so popular among many people, they believe it can't be traced.

I don't think my government would have the capacity, and knowledge, to find out, who are the Bitcoin owners. But centralised infrastructures, such as exchanges are definitely the weak points in this matter.