What is so fragile that saying its name breaks it?

It was a dark stormy night and a couple were in a car driving madly to a city. The car broke down and the husband had to go get help from someone who spoke his language. He was afraid to leave his wife alone in the car so he locked the car before leaving. When he came back, the car was in the same state as he had left it but his wife was dead, there was blood on the floor and there was a stranger in the car. What happened?

You measure my life in hours
I serve you by expiring
I vanish faster when I am thin
and slower when I am thick
The wind is my energy
What am I?

Do you know of a place where the wind blows south and then suddenly shifts direction towards the north?

Why do Chinese men eat more rice than Japanese men do ?

Can you think of any three-dimensional shape that comprises of exactly two surfaces?

Can you find a number that lies one third of the distance between 1/3 and 2/3?

Can you name some countries which do not have the alphabet 'A' in them?

Can you find the thief by just looking at the picture below?

Considering the below equation:

V + II - VI = 10
IV - X + VIII = 20
IV - VII + VI = 30

Then, I + II + III = ?