为什么是There are seven days in a week 而不是the seven days in a week 用不用这个不定冠词有何说法?如果此题用了the 是否是错的

为什么是There are seven days in a week 而不是the seven days in a week 用不用这个不定冠词有何说法?如果此题用了the 是否是错的 There are seven days in a week对seven提问 There are seven pencils in the pencilbox对seven提问 there are seven toys on the table用seven提问 There are forty students in Class Seven同义转换转换为：_____ ______ _____the students in Class Seven is forty There are seven days in a There are seven c_____ in the world. ( ) bowls are there in the cupboard.There are seven The shopping mall has seven floors.There are shops on each floor合并为一句 There are seven people in Liu's family.把There are seven people画线提问, there are seven sheeps over there哪错了 Seven percent of the population in the town are Germans为什么是are,不是is?population不可数吗? 同义句转换there are five people in Room A .there are seven people in Room B.合并为一句.there are five people in Room A .there are seven people in Room B.合并为一句.there are ------ ------in Room B than Room A there are seven ( ) in a week. they are ( ) ( ) ( ) ( ) ( )( )( )( )and( ). there are 12 months in 为什么是There are a pair of socks? There are seven days in a week 根据答句写问句 There are seven birthday in July.错哪了? There are seven days in a week这句话对吗