In 1890,about _____ of the land was covered by forests in the USA.

问题描述:

In 1890,about _____ of the land was covered by forests in the USA.
A.third
B.a third
C.the third
D.a thirds
这个怎么选,谢谢〜〜

选B,英语中表示分数时,分子要用基数词分母要用序数词,分子大于1时分母要加s.而这道题中是a,是单数所以不用加s,