In the sentence 'They often go to Italy because they love the food', 'They often go to Italy' is the main clause and 'because they love the food' is a subordinateclause.
在They often go to Italy because they love the food这个句子里,They often go to Italy是主句,because they love the food是从句。
《牛津词典》
2
All subordinateclause are trees leafage.
所有从句都是树的叶子。
3
A subordinateclause can not stand alone as a sentence - that is a sentence fragment.