（ ）Mary( )Sue knows nothing about the matter,( )they didn't go to school last Friday
问题描述：
（ ）Mary( )Sue knows nothing about the matter,( )they didn't go to school last Friday
A.Either;or;because
B.Both;and;as
C.Not only;but;for
答案给的是C,为什么不能选B呢?
答
Not only.but(also)连接主语,谓语采用就近原则,在这也就是与Sue保持一致,因此动词是三单形式knows.
而both.and连接主语,视为复数,因此应该是know