Were you born in a state whose right to citizenship you have never exercised? If so, then you might be eligible for citizenship through an unrestricted right of soil, also known as unconditional jus soli. This means that you have an automatic birthright to be a citizen of that country because you were born there. For example, if you are currently a British citizen who was born in the United States, you are entitled to American citizenship through unrestricted jus soli.  Research the immigration laws of your country of birth. Most countries do not grant citizenship through right of soil, so it is important to research the laws of the country in which you were born.  30 of the world's 194 countries practice unconditional jus soli. Of these 30 countries, Canada and the United States (as of 2010) are the only countries among the world's advanced economies that practice unconditional jus soli and grant citizenship to most children born on its soil, including children born to persons present in the state illegally.  However, children born in the United States to foreign diplomats and foreign heads of state do not acquire citizenship through right of soil. You may find that your country of birth, which is not the country whose citizenship rights you exercise, grants you a right to its citizenship through a right of soil. If so, discover how you can exercise that right.  One way to exercise a right to citizenship is to apply for a passport. You can apply for a passport through the state's embassy or consulate in your current country of citizenship and/or residence. You may be asked to present an original or certified copy of your birth certificate to the consulate or embassy as evidence. For example, if you apply for a Canadian passport, then you can present a birth certificate issued by the Canadian province or territory in which you were born. This serves as evidence of your Canadian citizenship because Canada practices unrestricted jus soli. Find out the laws regarding dual citizenship of both the state of your...

===
Write a summary of the previous text in Chinese:
先想想你的出生国是否允许你有第二个公民身份。 了解如何通过无限制国土权利行使公民权。 研究两国关于双重国籍的法律。