Bonjour,

Réponse :

4/

a. In the video the couple is changing clothes.

b. They look very happy and they are smiling.

c. They are having fun.

5/

a. Is the man wearing a tie and a hat?

b. Are the man and the woman wearing a hat?

c. Is she holding a hadbag and wearing sunglasses?

Explications :

                      PRESENT BE + V-ing

Forme affirmative : I am + V-ing

                                You/We/They are + V-ing

                                He/She/It is + V-ing

Forme interrogative  :  Am + I + V-ing .....?

                                    Are + you/we/they + V-ing ...?

                                    Is + he/she/it + V-ing ....,