第六部分∶完形补文（第41～50题，每题 1.5分，共15分）
下面的短文有 10处空白，每处空白后的括号内有一个词，请根据短文内容将其正确的形式填入文中，以恢复文章原貌。
The Origin of Birthday Cake
The words for"cake"and "bread"were practically (practical) the same in early Europe. The only 41_______________(differ)was that cakes were sweet. In the 15th century,42_______________(baker)came up with the idea of 43_______________(sell) cakes for people's birthdays and their weddings. Since the cakes were 44_______________(usual) used for the birthdays of young children, these celebrations were 45_______________(refer) to as children's festival. During this period,people began to put new ingredients（成分） into cakes to make them 46_______________（sweet） and less bread-like.
During the 17th century，birthday cakes were a luxury（奢侈品）. Only the very 47_______________(wealth) could afford them. During the 48_______________(Industry)Revolution, materials and tools became more advanced and more 49_______________(easy) acquired.As a result, the price of birthday cakes became 50_______________(accept) to the masses.