Someone was beating a drum.

　　有人在敲鼓。

　　Someone was pounding at the door.

　　有人在砰砰地敲門。

　　Someone was ringing the doorbell.

　　有人在按門鈴。

　　Someone has taken my scarf.

　　有人把我的圍巾拿走了。

　　I need someone to help me.

　　我需要有人幫我。