When talking about something that happened in the past, the correct verb tense isn't always enough - sometimes you need a temporal expression to state just when it happened. The most common French temporal expressions are depuis and il y a, and they are not interchangeable.
Devoir is a very common French verb with irregular conjugations and an unusual relationship to some of its English equivalents. It has several meanings related to obligation, supposition, and expectation.
A direct object is a noun, whether person or thing, that someone or something acts upon or does something to. In both French and English, direct objects are often replaced with direct object pronouns (COD): me, te, le, la, nous, vous, les.
The preposition en can be summarized as "to or in," but it's a bit more complicated than that.
The preposition entre usually means "between" or "among."
French grammar is sometimes trumped by pronunciation, as in the case of euphonic adjectives. Because French does not like the hiatus created when a word ending with a vowel precedes a word that begins with a vowel or mute h, a few adjectives change their spelling—and thus their pronunciation—for purely euphonic reasons.
When inversion results in a hiatus (two vowel sounds together), the letter -t must be added for euphony, but only under two conditions.