Three-fourths of the homework [ ]today.

问题描述:

Three-fourths of the homework [ ]today.
A;has finished
B;has been finished
C;have finished
D;have been finished
必须有理由

选B,homework 是个单量,用单数动词,has .然后这是一个被动语态,所以用has been.
由此答案选B