-which is more useful,biology or chemistry -i think ___them is useful.

题目

-which is more useful,biology or chemistry -i think ___them is useful.
-which is more useful,biology or chemistry
-i think ___them is useful.
a.either of b .none of c,both of d.all of 选哪个 ,回答,急

答案

a.either of -which is more useful,biology or chemistry -i think ___them is useful.生物和化学哪一个更有用?我觉得每一个都有用.首先是因为前边问题中只涉及两项生物和化学,所以排除b 和d 都表示三者或三者以上....