Esp 4 -Por y para

through
ie:  I walk through the river.

Deadline, point of time in future
ie: The homework is for Tuesday.

Compare/Contrast
ie: For such an organized person, his handwriting is awful.

Cause, because of, on account of
ie: Because he studies, he gets decent grades.

"in order to"
ie: I call my mom in order to ask her for money.

along
ie: I walk along the river.

means (of transport)
ie: Please send me your resumé by e-mail.

in search of
ie: I went to the library for a book.

means ie: My package was delivered by UPS.

duration of time
ie: I studied for my math test for 25 minutes.