Prepositions

This again is not an easy topic. The prepositions used after many adjectives or verbs (to introduce their object) are often different from other languages. For instance, something isn't "different of" or "dependent of" in English, as it would be in French, it is "different from" or "dependent on."

In some cases, there isn't really a difference, it is simply that the French "de" can be translated to "of" or "from" depending on its meaning. But in the case of "dependent on," there is simply a usage difference.

There is no structural rule to rely on, you just have to learn these expressions...

Similar to
Different from
To dissociate from
According to (French speakers may omit "to" by mistake, thinking of "d'après" or "selon")
Relative to
The best solution in the world (not "of")
The number of records in the file (ditto)
It is considered a conflict of interest (not "considered as")
This program splits one file into two (not "in")

The case of the word "compared" is interesting, because you can use "to" or "with" to introduce the object. However, purists make the following distinction:

use "compared to" if the comparison reveals mostly similarities, or you compare something or someone to something or someone else he/she/it aspires to be closer to: "Bush would like to be compared to Churchill."
use "compared with" if the comparison exhibits mostly differences, or the intent is to distance the subject from the object of the comparison: "Bush's statements on the environment are 'interesting,' when compared with Clinton's."

Sometimes, a preposition is needed in one of two similar forms, but not in the other form. The following two forms are correct:

You may access this file
You may have access to this file

... but you cannot mix them!

Similarly, the order in which multiple objects are introduced may impact the use of prepositions. The following two forms are both correct, but notice how the use of prepositions changes:

Ask for the access code from the administrator
Ask the administrator for the access code

The form just above is particularly confusing to French speakers not fluent in English, because in French you need a preposition for the indirect object, not for the direct one, which is the contrary of what happens with the verb "to ask" in English. Thus French speakers will often be heard saying "Ask the access code to the administrator," which is doubly incorrect and very confusing to a native English speaker.

Often, a verb and a preposition form a "verb phrase" whose meaning is as dependent on the preposition as it is on the verb. For instance:

to "look for" is to search around a place,
to "look at" is to contemplate,
to "look up" is to search in a directory or dictionary,
to "look into" is to research more completely,
to "look up to" is to emulate someone,
to "look forward to" is to eagerly anticipate,
etc.

Again, you just have to learn these.

And finally, the same preposition may be repeated with different meanings, in such a way that an English speaker will not even notice the apparent repetition:

He has been looking for a solution to this problem for a month (not "since a month")