Exercice 1 : Réécris les phrases suivantes en utilisant while + BV + ing quand c'est possible. 1- Did you hear the alarm while you were waiting for the bus ? 2- The police arrived while the two burglars were opening the safe. 3- The detectives kept silent while they were drinving back to the police station. 4- They arrested the thieves while they were trying to use a stolen credit card in a petrol station. 5- Did you speak to a CSI star while you were staying in Las Vegas?