I'm not totally sure what you mean by losing SP, but my guess is that it's like this. As a new user the SP in your wallet has two lines, like yours says:
0.193 STEEM
(14.807 STEEM)
And maybe before it said:
0.100 STEEM
(14.900 STEEM)
The number in parentheses is a loan that Steemit Inc is giving you to help you start up your account. It keeps you at 15 total SP so that your bandwidth allowance is enough to post, vote, and comment. As you earn your own SP closer to 15, that number will go down and eventually go away. Once you have more than 15 the SP is all yours.
It looks like the main thing for you to improve is to read a lot in English, post, and develop your language skills. There might also be a community here in your native language.
Thank you so much for your valuable information.My sp was 15.10 before 2 days.But i don't understand why it decrease suddenly.my sp is now 15.00
Your SP really is 0.193. And the only way for that number to go down is if you choose to power down.
The rest isn't yours, it's just there to help you as a new user.