Question

Put the verbs into the correct form (past perfect progressive).
They (wait) at the station for 90 minutes when the train finally arrived.
We (look for) her ring for two hours and then we found it in the bathroom.
I (not/walk) for a long time, when it suddenly began to rain.
How long (learn/she) English before she went to London?
Frank Sinatra caught the flu because he (sing) in the rain too long.​

Answer 1

Respuesta: 1  waited 2 looked for 3 had not walked 4 she learned 5 sung

Explicación: Porque la 1 la 2 la 3 y la 4 son verbos regulares y la ultima no se la regla.