A major cause of mistakes in a second language is interaction with the first language. It is interesting to study why learners make certain mistakes because we can gain insight into the differences between the way French and the native language work. Here are two examples of a certain mistake that I keep hearing from English-speaking learners of French:

* Je pense souvent de toi. (I think of you often.)
* Il pense de partir demain. (He’s thinking of leaving tomorrow.)

These are two glaring mistakes that should be avoided. Here are the correct forms:

Je pense souvent à toi.
Il pense partir demain.

Why do people make these mistakes in French?

There are two distinct mistakes here, but both have the same origin. The problem comes from the translation of the English “to think of” or “to think about.”

Remember that “to think of” has two different meanings. A first meaning is “to have an opinion about someone or something.” When asking for an opinion, French would use the following construction:

Que pensez-vous de cette declaration ? (What do you think of this statement?)
Que pense le gouvernement de l’idée ? (What does the government think of/about the idea?)

Seeing that “of” is translated by “de”, many users conclude that “penser de” means “think of.”

But “to think of” also means to “have someone or something in one’s mind.” Some learners assume that “penser de” can be used for this meaning. A big mistake. In French, this second meaning is conveyed by “penser à.” which many people may avoid because it seems to mean “think to.” Here are some examples,

Je pense aux vacances déjà. (I’m already thinking of the holidays.)
Il faut penser aux moins riches que nous. (We must think of those less fortunate than us.)
Je pense à toi tous les jours. (I think of you every day.)
Nous avons pensé à tout. (We’ve thought of everything.)

This use of the preposition “à” leads us to use the pronoun “y” when referring to something that already has been mentioned. Here are two examples:

Je vais y penser et je vous répondrai demain sans faute. (I’ll think about it and I’ll get back to you tomorrow without fail.)
Pensez-y avant de partir. (Think about it before leaving.)

We can also use what are called relative pronouns based on this “penser à” construction, as in:

Voici la solution à laquelle je pense. (Here is the solution I’m thinking of.)
C’est un livre auquel je pense souvent. (It’s a book that I think of often.)

The second mistake (“*Je pense de partir”) also stems from the incorrect translation of “think of” by “penser de,” In English, when “think” is followed by a verb, it is usually in the following form:

I’m thinking of leaving soon.
We’re thinking of leaving early.
She had thought of coming next week.

Many English-speakers use “penser de” because of this idea of “to think of”, leading to the common mistake.

To understand why this is wrong, we have to look at detail of French grammar. It is important to understand that in French when a verb is followed by another verb, three things can happen: 1) we use the preposition “de” between the verbs; 2) we use the preposition “à” between the verbs and 3) we do not use any prepositions at all between the verbs. Let’s look at these situations

Verbs with “de”

These include: essayer, décider, tenter, s’approcher. etc. Here are some examples:

J’ai essayé de vous appeler. (I tried to call you.)
Nous avons décidé de partir demain. (We have decided to leave tomorrow.)

Verbs with “à”

These include: chercher, tenir, commencer, s’amuser, inviter, etc. Here are some examples:

J’ai cherché à comprendre. (I tried to understand.)
Nous avons tenu à vous rencontrer. (We insisted on meeting you.)
Vous êtes invites à prendre place dans la salle. (You are requested to take your seat in the hall.)

Verbs with no preposition between them

These include: aimer, aller, venir, vouloir, pouvoir, préférer, laisser, penser, etc. Here are some examples:

Vous pouvez partir maintenant. (You can leave now.)
Je préfère commander tout de suite. (I prefer to order right away.)
Nous allons acheter une maison. (We are going to buy a house.)
Ils viendront manger avec nous. (They will come to eat with us.)

The special case of “venir de”

Remember that “venir de” means “to have just …”, as in the following examples:

Je viens de manger. (I’ve just eaten)
L’avion vient de décoller. (The plane has just taken off.)

Otherwise, “venir” does not take a preposition before the next verb. I should also mention that there are verbs that use both “de” and “a” with slight nuances of meaning.

Using “penser “

Here are some more examples with “penser.” Notice how these examples are translated.

Je pense partir demain. (I’m thinking of leaving tomorrow.)
Quand pensez-vous arriver ? (When do you think you will arrive,)
Que pensez-vous faire alors? (What do you think you will do then.)
Nous ne pensons rien décider pour l’instant. (We don’t think we’ll decide anything for the time being.)

As you can see from all these examples, “penser de” is actually quite rare and is basically limited to the question form “Que pensez-vous de?” (What do you think of?) Otherwise, there is no reason to use it. Avoid this common mistake by thinking “penser à” and “penser + verb.”