Who can help me explain the difference between musical and opera in English?

Opera is an art form in which singers and musicians perform a dramatic work (called opera), which combines a text (called a script) and a musical score. Musical is a dramatic form that combines music, songs, oral dialogue and dance.

Opera is a part of western classical music tradition. This kind of performance is usually performed in the opera house, accompanied by an orchestra or a smaller music group.

Modern musicals are not that old. It was mainly developed in the 20th century. They may perform in large performance venues, such as the big budget West End and Broadway theaters in London and new york, or tour in smaller marginal theaters, off-Broadway or regional performances, or be performed by amateur groups in schools, theaters and other performance venues.