Réponse:
Bonjour.
1) He has been playing tennis since he was 11 years old.
2) He has won the national championship 4 times.
3) For how long she has known him? Since Valentine's day.
4) I've been surfing the net since 2 pm.
5) They have been playing video grames since they arrived.
6) How long they've been studying spanish? For two years now.
7) Look! She's been to the hair salon! She looks lovely.
Bonne journée!