Does penser require the subjunctive?
Penser may require the subjunctive, depending on whether it is used affirmatively, negatively, or interrogatively:
Je pense qu’il veut aller avec nous.
I think he wants to go with us.
Je ne pense pas qu’il veuille aller avec nous.
I don’t think he wants to go with us.
Penses-tu qu’il veuille aller avec nous ?
Do you think he wants to go with us?
À noter : The above is correct according to Le Bon Usage and Le Grand Robert, among others. However, so many native speakers mistakenly use the indicative when penser is in the negative or interrogative that many now believe the subjunctive to be optional. Others disagree.