答案：D

题目分析：考查名词辨析。句意：信不信由你，英语中部分单词起源于法语。in demand急需；in principle原则上；in theory理论上；in origin起源于。如：One of two or more words that have the same spelling but differ in origin, meaning, and sometimes pronunciation.同形异义词两个或以上单词拼法相同，但在起源、意义和有时读音上不同。