all at once的音标：all at once的英式发音音标为：[ɔ:l æt wʌns]all at once的美式发音音标为：[ɔl æt wʌns]...

All at once, Mick's serious expression softened into a grin.米克严肃的表情一下子变成了笑脸。All at once there was someone knocking on the door.忽然有人敲门。I feel terribly sleepy all at once.我突然觉得特别困。...

突然，同时...