I think about Marie
Je pense à Marie
to think about (someone, something) - penser à. In this case "about" is translated with the preposition à. Very common in French, à can have various meanings -- including "to" and "toward" -- depending on context.
I have a good book
J'ai un bon livre
a book - un livre
She is a teacher
C'est une enseignante
a teacher - un enseignant. Note that it is common to use c'est rather than il/elle est, even for a person. C'est must be followed by an indefinite article (un/une), while il/elle est should NOT: Elle est enseignante.
She is a (primary school) teacher
C'est une institutrice
a teacher (primary school) - un(e) instituteur/-trice. Note that when addressing primary (and sometimes middle) school teachers, students usually use the noun maître/-esse.
a (middle/high school) teacher, a professor
a (middle/high school) teacher, a professor - un professeur. In written form, professeur is always a masculine noun. When spoken, especially with the colloquial abbreviation prof, you can use the feminine form -- une prof.
It's an American school
C'est une école américaine
school - l'école
The middle school is big
Le collège est grand
middle school - le collège. Note that the French word for "college" or "university" is the feminine université.
a good high school
un bon lycée
high school - le lycée. Note that although most nouns ending in an "e" are feminine, lycée is masculine.
I study mathematics
J'étudie les mathématiques
to study - étudier. After étudier, you should always use an article before the noun. Note also that mathématiques is a special noun that can only be plural.
She is studying with a friend
Elle révise avec un ami
to study, to review, to revise - réviser. Note that this verb is different from étudier, which means to study a subject regularly or in general. Réviser pertains instead to studying for something specific like an exam or a quiz.
She enters the house
Elle entre dans la maison
enter - entrer
I am studying at home
J'étudie à la maison
at home - à la maison. This literally translates to "at the house."
They are coming (back) home
Ils rentrent à la maison
to come home, to come back - rentrer. To express "to come (back) to" you use rentrer à, while to express "to come (back) from" you would use rentrer de.
We're finally home
Nous sommes enfin à la maison
finally - enfin
The boys are interesting
Les garçons sont intéressants
interesting - intéressant
Is he a professor?
Note that things are often inversed in questions, such that the pronoun comes after the verb, joined by a dash. Another example: "Do you have my book?" translates as As-tu mon livre?
Are you guys classmates?
Êtes-vous camarades de classe?
a classmate - un(e) camarade (de classe)
We have homework
Nous avons des devoirs
homework - les devoirs. Used here as a plural masculine noun, devoir is also a verb, meaning "to owe" or "to have to."
You speak very quickly
Tu parles très vite
quickly - vite. Note that when an adverb (in this case, très) modifies another adverb (vite), it precedes that adverb.
I am often sad
Je suis souvent triste
often - souvent. Note that when adverbs modify adjectives, they usually precede the adjectives.
We're coming home by car
Nous rentrons (à la maison) en voiture
to go home by (means of transportation) - rentrer en. The preposition en can be used to introduce most modes of transportation. Note that en can also mean "in" or "inside."
You (singular) live a good life
Tu vis une bonne vie
to live - vivre. This is an irregular verb: je vis, tu vis, il/elle/on vit, nous vivons, vous vivez, ils/elles vivent.
I live in France
J'habite en France
to live, to reside - habiter. Note that habiter is a regular -ER verb. Also note that it is different from vivre in that it is used to speak about one's place of residence.
We're coming home by train
Nous rentrons (à la maison) en train
a train - un train
What are the present tense conjugation endings of 2nd group (-IR) verbs?
-is -is -it -issons -issez -issent
For example, for finir, which means "to finish": je finis, tu finis, il/elle/on finit, nous finissons, vous finissez, ils/elles finissent.
I choose to work
Je choisis de travailler
to choose - choisir. Note that you translate "to choose to" with choisir de. In the first-person singular of the present tense, regular -IR verbs take the ending -is.
You react badly
Tu réagis mal
to react - réagir. In the second-person singular of the present tense, regular -IR verbs take the ending -is.
Is the train long?
Le train est-il long?
long - long. Note that the feminine form is longue.
Does she concentrate well?
to reflect, to ponder, to concentrate - réfléchir. In the third-person singular of the present tense, regular -IR verbs take the ending -it.
We are growing old
to age, to grow old - vieillir. In the first-person plural of the present tense, regular -IR verbs take the ending -issons.