[A] Tom, horrified at what he had done, could at first say nothing; Romeo, believing that Juliet was dead, decided to kill himself; A man carrying a large parcel got out of the bus. Jones and Smith came in, followed by their wives; She rushed past the policeman, hoping he wouldn’t ask what she had in her suitcase. Stunned by the blow, Peter fell heavily, (Peter had been stunned); Believing that he is alone, the villain expresses his thoughts aloud. «Waiting for a bus a brick fell on my head» : «As I was waiting for a bus a brick fell on my head» ; » *When using this machine it must be remembered …» : «When using this machine you must remember …» ; » *Believing that I was the only person who knew about this beach, the sight of someone else on it annoyed me very much» : «As I believed I was the only person etc.» , o bien: «Believing that I was the only person on the beach, I was annoyed by the sight of someone else.»
[A] Un participio se considera que pertenece al nombre/pronombre que lo precede, pero a veces el participio puede estar separado de su nombre/pronombre por un verbo principal; y si no hay nombre/pronombre en esa posición el participio se considera que pertenece al sujeto del siguiente verbo principal. Cuando no se observa este principio, se produce confusión: «Waiting for a bus a brick fell on my head», por ejemplo, sugiere que el ladrillo estaba esperando el autobús, lo que no tiene sentido. Un participio vinculado de esta manera al nombre/pronombre erróneo se dice que esta «mal concertado,» «misrelated.» La frase de arriba debería reescribirse como «As I was waiting for a bus a brick fell on my head.»
A Practical English Grammar (A.J. Thomson & A.V. Martinet) 