LZM语法上的几个问题

1。LZM书上说表示“目的是，旨在”用aim to do sth., 不是aim at doing sth., 可我查字典，字典上说的正好相反。到底是什么呢？

2。 请问compare to/compare with  用法怎么区别？一个用在物一个用在人？

3。也是LZM书上的：

Before the Civil War, Harriet Tubman, herself an escaped slave, returned again and again to Maryland to guide other slaves along the Underground Railroad to freedom.

A) herself an escaped slave, returned again and again to Maryland to guide

B) being an escaped slave herself, returned again and again to Maryland so as to guide

C) an escaped slave herself, returned again and again to Maryland for guiding

D) herself as an escaped salve, returned again and again  to Maryland so as to be the guide of

E) who had been herself as an escaped slave, returned again and again to Maryland for the guiding of

不能理解A为什么对

4。During Roosevelt's years in office, Black Americans began voting for Democrats rether than Republic in nations elections, but Black support for Democrats at the state and local levels developed only after when civil rights legislation was supported by Harry Turman.

A)developed only after when civil rights legislation was supported by Harry Turman.

B)developed only after when Harry Turman supported civil rights legislation

C)develpoed only after Harry Truman's support of civil rights legislation by Harry Truman

D) develops only at the time after the supporting of civil rights legislation by Harry Truman

E)develpoed only after there being Harry Truman's support of civil rights legislation

答案是C，不明白。画线部分是什么意思呢？

"3, in  = in order to"

What does this mean? Thanks.