there is a book and three pen on the chair. there are three pen and a book on the floor. 这两句话中,为什么第一句话不用are,表复数关系?
There is a book and three pens on the chair. 用 is 是[就近原则], 因 book 是单数There are three pens and a book on the floor. 用 are 也是[就近原则], 因 pens 是复数如:There is a girl and two boys in the room.There are two boys and a girl in the room.
答:复数就是实数,虚数和的形式是最大的数集。字母为Z。 虚数是以根号-1为单位的数符号j或i,j或i是根号-1的意思。实数是以根号1为单位的数。两者的数轴是正交的。...详情>>