【小题1】It was raining heavily when he ________ home last night.
【小题2】Mary wonders what she _________ as when she grows up.
【小题3】— Amy, I called you yesterday evening, but nobody answered the phone.
— Oh, I ________ a walk with my mother at that time.
【小题4】—________ you ________ a letter to your mother recently?
—Yes, I wrote one last Sunday.
【小题5】We are told that sound ___________ through air at a speed of about 340 metres per second.