Question

I () my brother when someone knocked at the door

I () (telephone)my brother when someone knocked at the door

Answer 1

I ( was telephoning )my brother when someone knocked at the door.

一定要用过去进行时,这是一个固定句型:

sb. be doing sth. when ... 某人正在做某事,这时突然...

句意:我正在给哥哥打电话,这时突然有人敲门.

Answer 2

waked，叫醒。