请根据句意从方框中选择合适的动词，并用其适当时态填空，使句子通顺。

It was raining heavily when he ________ home last night.
Mary wonders what she _________ as when she grows up.
— Amy, I called you yesterday evening, but nobody answered the phone.
— Oh, I ________ a walk with my mother at that time.
—________ you ________ a letter to your mother recently?
—Yes, I wrote one last Sunday.
We are told that sound ___________ through air at a speed of about 340 metres per second.