Using a functional resume format is beneficial when you have gaps in employment. The functional resume highlights honors and achievements more than work experience. It lists your skills and other attributes that make you a good employee at the top of the resume. It is important to fill the gaps in employment with experiences that helped you grow. Volunteer work, continuing education, and other projects you worked on during that time are all great options. Be sure to use a positive tone while describing the gaps in employment and be confident about them when interviewing later.
In the United States, a CV is almost exclusively limited to professions in academia, science and medicine. In the case of academia, the main focus of the CV should be to identify yourself as a scholar. The added length, should be filled with proof of your skills as a teacher, scholar, and your knowledge of education. A CV should be thought of as a living document, and it will change frequently based on the updates in your education and career.