The process to becoming a U.S. citizen, called naturalization, begins with the applicant's demonstrated commitment to the United States. In general, for adults over the age of 18, while there are some exemptions, the naturalization process is open to legal permanent residents who have been in continuous residence in the U.S. for at least a period of 5 years. Upon submission of Form N-400, the Application for Naturalization, and the fee, typically $675, the United States Citizenship and Immigration Services (USCIS) investigates the applicant's background and eligibility for the citizenship process. The applicant is then prompted to submit to an FBI background check. Once completed, the USCIS notifies the applicant that an appointment has been scheduled for his interview. At the interview, the applicant will face questions requiring him to verify his background information and his motives in becoming a U.S. Citizen. During the interview the applicant will also be tested on his ability to read, write and speak English and his knowledge of U.S. history and government. Once the applicant has successfully passed through the background checks, tests and the interview, he will be asked to pledge the Oath of Allegiance, after which he will be a full citizen of the United States. Sometimes, in certain areas, the applicant is able to take the Oath on the same day of his interview. In other cases, the applicant is notified by mail on the approval or denial of his application; in this circumstance, the approval will indicate a scheduled time and location for the applicant to take his Oath.