IF I can sing well enough, I'll join the school chorus.
The IF implies that something is conditional i.e. it may happen, it may not happen (it depends on whether you can sing well enough!)
Hope this helps... :)
The two words Bradbury uses repeatedly in this scene are "The beetle". The repetition adds to the suspense of the scene. Each time "the beetle" is repeated the reader can feel the car getting closer and closer. Because the sentences are very short and similarly structured, they speed up the pace of the scene just like the car is picking up speed.
The mood (or tone) of the prologue is considered as sombre, dark, macabre... since from the start we're being told that this story is going to be a story of love, death and loss.
