復合句
復合句分為并列復合句（也稱并列句）和主從或從屬復合句（也稱復雜句）。
Beijing is in the North and Nanjing is in the South.
特點：When two independent clauses, or complete sentences are joined together, they form one compound sentence.
復合句是由兩個獨立的句子組合在一起構成的。例句中，有下面兩個完整并且獨立的句子組成：
Beijing is in the North.
Nanjing is in the South.
復雜句
復雜句，某個句子成分直接由從屬分句表示，那么這種句子便不是簡單句而是復雜句。
My uncle, who is seventy years old, works on a farm.
特點：When an independent clause and a dependent clause are joined together; they form one complex sentence.
復合句是由一個獨立的句子加一個從句構成的。
China is a country that its history is very long.
China is a country.(獨立句子)
That its history is very long(從句)