Michelle Obama is the first African-American to assume the role of First Lady.
问题描述：
Michelle Obama is the first African-American to assume the role of First Lady.
Michelle Obama is the first African-American to assume the role of First Lady.这句是简单句还是并列,复合?to assume the role of First Lady做什么成分
答
是简单句.应该是不定式短语做 African-American的补语