请教各位 compare with 和 compare to 的用法

一直想问一下，”compare to” and “compare with”有什么不同呀。在很多题里面见过，可就是想不通。拜托哪位大侠指点一下，下面是有关两题。

555:  One noted economist has made a comparison of the Federal Reserve and an automobile as racing through a tunnel, bouncing first off one wall, then the other; the car may get where it is going, but people may be hurt in the process.

(A) made a comparison of the Federal Reserve and an automobile as racing through a tunnel, bouncing

(B) made a comparison between the Federal Reserve and an automobile racing through a tunnel, bouncing

(C) compared the Federal Reserve with an automobile as racing through a tunnel and which bounced

(D) compared the Federal Reserve to an automobile racing through a tunnel, bouncing

(E) compared the Federal Reserve with an automobile that races through a tunnel and it bounces

558:  One of four babies are now born to mothers aged thirty years or more, compared with just one of six born in 1975.

(A) of four babies are now born to mothers aged thirty years or more, compared with just one of six born

(B) of four babies is now born to a mother whose age is thirty or older, compared to just one of six babies who were born

(C) baby in four are now born to mothers aged thirty or older, compared to just one in six

(D) baby in four is now born to a mother aged thirty or older, compared with just one in six

(E) baby in four is now born to mothers aged thirty years or more, compared to just one in six

Answer key= D, D

Compare A （Federal Reserve ）to B（an automobile racing） :  把A 比作B（比喻的意思， A， B不同类）

Compare A with B：A 和B 比较（A， B同类， 所有的比较：numbers, ratios,etc.)