The prepositions à and de are found in many verbal constructions that look very similar, but the choice of preposition makes all the difference.
The regular -er verb aimer is ubiquitous and very useful, but somehow means both "to like" and "to love." In some contexts, this can make a world of difference as you certainly don't want to tell someone you love them when you're just friends, so how can you make it clear how you feel?
Aller is one of the most common and useful French verbs and has irregular conjugations in most tenses and moods. Aller literally means "to go" and is required to create the near future.
The French verb arriver usually means "to arrive" or "to happen." It's a regular -er verb that requires être as its auxiliary verb in compound tenses/moods.
Avoir is one of the two most important French verbs and has irregular conjugations in just about every tense and mood. Avoir literally means "to have" but also serves an an auxiliary verb and is found in many idiomatic expressions.
Certain aspects of French grammar are a bit different with the causative than with other two-verb constructions.
Croire literally means "to believe" but has somewhat varying meanings depending on the preposition used. Learn the difference between croire à and croire en, plus other uses of croire.
Devoir is a very common French verb with irregular conjugations and an unusual relationship to some of its English equivalents. Devoir has several meanings related to obligation, supposition, and expectation.
Devoir and falloir are fairly synonymous, but these two French verbs are not interchangeable. Their meanings are slightly different, and they each have additional meanings, depending on how they're used.
Dire is one of the most common and useful French verbs and has irregular conjugations. It literally means "to say" or "to tell," and is also found in many idiomatic expressions.
Two dozen French verbs always require a reflexive pronoun but aren't necessarily reflexive or reciprocal. These "essentially pronominal" verbs can only be used pronominally, as without the pronoun, the verb is meaningless.
Être is one of the two most important French verbs. It literally means "to be," but also serves as an auxiliary verb and is the key to the passive voice.
Faillir has no direct verbal English equivalent when used as a semi-auxiliary verb; English needs an adverb or a short phrase to capture the meaning, such as "to almost do."
The causative is a grammatical construction with a lazy subject who, rather than performing some action himself, is making someone or something else do it: to make something happen, to have something done.