How do I check the process of mining, ie the percentage of a block to be finished ? I have started the mining process, and the CPU is always 100%, I'm just wondering how far along that CPU work brought me to the goal of finding a block. Where could I check the progress? Thank you.
...the percentage of a block to be finished?
It's not like a progression to completion, rather how many times you've tried to find a solution. If the network difficulty is 10, you'd likely find a block by the time you've tried 10 times, but you might find on the first try or any number of attempts.
If you want to track your luck, it's simply the amount of hashes you've tried divided by the network difficulty. If your hashrate is 20 KH/s, then 20,000 multiplied by the duration (in seconds) you've been mining gives you how many hashes you have tried.
The mining process is a memory-less one. Calculating a hash to see whether it yields a valid block does not bring you closer to the goal in any meaningful sense.
You can understand the process with a metaphor: imagine you are working QA at a plant manufacturing widgets, and you're trying to take defective widgets away before packaging. The manufacturing process will produce defective widgets with some small probability, and the only way you have to tell if a widget is defective is to try it.
Then you get to test widget after widget. But if you test a widget and it works fine, you don't get any closer to finding a defective widget. The next one you test is not more likely to be defective just because you the one you tested before was working. That's the same idea here. You don't progress towards a goal, though on average you'll find a defective widget every N minutes. Sometimes you'll find a defective one quick, and sometimes you'll get a long string of working widgets.