Sabotage (1935, Alfred Hitchcock)

tHIS FILM IS AN EXAMPLE OF SUSPENSE. THIS FILM ALSO FEATURES the use of dramatic irony. we know its a bomb but the boy doesn't. it builds suspense as you don't know if he is going to get to the station on time or if the bomb will kill him and the passengers on the bus. the background music sounds like a clock to emphasize the technique of suspense and hence lead to the shock.