Use Present Perfect Continuous or Past Perfect Continuous 1.Why are you so dirty? I (play) football with my friends 2.How

1. Why are you so dirty? I have been playing football with my friends 2. How long have you been learning Arabic? 3. Kate was very tired, she had been doing her room since afternoon. 4. We have been waiting for the train for half an hour.

В третьем примере использован глагол \"was\", задающий фон прошедшего времени, следовательно предложение необходимо оформить в Past Perfect Continuous.