When they send e-mail messages, they only have to pay for their phone calls to their local service providers. определите вид придаточного предложения

Определите вид придаточного предложения:( обстоятельственное, определительное и именное). Проанализируйте члены в обоих предложени When they send e-mail messages, they only have to pay for their phone calls to their local service providers.