Simplify the following text for a Grade 7 native English-speaking person.
Original: Because non-musical stage plays generally have no requirements for vocal range , they do not usually contain breeches roles in the same sense as opera . Some plays do have male roles that were written for adult female actors , and ( for other practical reasons ) are usually played by women ( e.g. , Peter Pan ) ; these could be considered modern-era breeches roles .
Simplified: Sometimes breeches roles are in plays , but they are usually in opera .