I. 1)  mystérieux = puzzling
de grande valeur = valuable
frotter = to rub
murmurer = to whisper
pour l'amour du ciel = for heaven's sake
sangloter = to sob
regarder attentivement = to stare
faire sursauter = to startle

2) This story is an excerpt from a crime fiction (roman policier) because it's about a mysterious case involving a detective.

3) Two characters : the detective Jack Ekse and Lady Winterwind
4) The scene takes place in Lady Winterwind's house.
5) The story takes place in Great Britain. Two elements allow us to argue that : the detective is from Scotland Yard and the writer uses "Lady" Winterwind, which is typical of Great Britain.
6) One valuable painting has been slashed for an unknown reason and a message has been discovered
7) The woman is extremely upset, she cries, she shouts, her hands are shaking...
8) Jack Ekse seems very phlegmatic
9) a. Wrong. "the famous Scotland Yard Detective"
b. Right. He is famous so it means it solved many cases like this
c. Wrong. She detains one of the most valuable paintings in the world
d. Wrong.