1. 在此than是即做连词又做"关系代词",既然是关系代词,那么就应该像定语从句一样后面补出谓语动词。可是A选项没有谓语动词。而且这里用“局部概念比较”更简洁,所以B比A好。
2. in和of都可以用,只是表达的内在含义稍有不同。in是范围概念,of是属性概念。前面的with也是一个属性概念,用of更加呼应一点,但是这点不会成为考点的。
-- by 会员 aeoluseros (2011/8/3 10:16:27)
A) lower than in
You would only compare two prepositional phrases when you are comparing something to itself.
Correct: Sue reads more at night than in the day. (The sentence compares the two time periods.)
Incorrect: Sue reads more than at night. (There is a second time period but no first time period to complete the comparison.)
In A, there is no first prepositional phrase to complete the comparison ending with "...than in the most impoverished countries..."
来自GMATclub
-- by 会员 balapupu (2011/8/3 11:12:09)