1. Bihar is India’s poorest state, with an annual per capita income of $111, lower than in the most impoverished countries of the world.

(A) lower than in

(B) lower than that of

(C) and lower than that of

(D) which is lower than in（B）

(E) which is lower than it is in

为什么B中是用THAT OF——单数？我觉得应该用复数啊

1. Bihar is India’s poorest state, with an annual per capita income of $111, lower than in the most impoverished countries of the world.

that 是指 annual per capita income 所以是单数。这道题是考比较。首先比较的两个东西必须有可比性。这道题是 the annual per capita income of Bihar 和 the annual per capita income of the most impoverished countries of the world 比较。因为，在 than 之前已经出现了annual per capita income, 所以在than 之后将它指代为that.

楼上说的我懂，我是觉得为什么the most impoverished countries 的annual per capita income会用单数？难道这些国家只有一个annual per capita income？说不通啊？

请大家指教

不对啊，应该是每个国家都有自己的annual per capita income吧，怎么会是几个国家只有一个annual per capita income？

我都觉得我很麻烦，但我就是想不通~~~~~~~~~~~