Pendant, Dans, En, Depuis and Il y a

a. Dans: express event in present or future

Elle va arriver dans dix minutes.

She will arrive in 10 minutes

b. Il y a: express event in the past

Elle est arrivée il y a 12 heures.

It has been 12 hours since she has arrived.

c. Pendant: it is used to express an event in the past that is ended.

Nous avons attendu pendant deux heures.

We have waited for two hours.

d. En: indicates time needed to do something

Je vais être prêt en deux minutes.

I will be ready in two minutes.

Il finit son cours en six mois.

He will finish his course in six months.

e. Depuis:

e.1 In the Present tense, indicates something the has been going

J’etudie francais depuis l’année derniere.

I study French since last year.

e.2 In the Passé Composé tense, depuis indicates something that has’nt been going anymore.

Depuis qu’il est partie, je ne sors plus.

Since she has left, I don’t go out anymore.