Simplify the following text for a Grade 4 native English-speaking person.
Original: Due to their statuses as colonies of foreign states during the establishment of the People 's Republic of China in 1949 , the term `` mainland China '' excludes Hong Kong and Macau . Since the return of Hong Kong and Macau to Chinese sovereignty in 1997 and 1999 , respectively , the two territories have retained their legal , political , and economic systems .
Simplified: The term also excludes Hong Kong and Macau .