假如你叫李華，你校英文報下一期專欄的話題是"講述一件令人難忘的事情"．請根據(jù)下面提供的開頭部分，發(fā)揮你的想象力就此話題續(xù)寫該短文，然后向該專欄投稿．
要求：1．文中使用情態(tài)動詞表示推測的句子至少兩句；
2．文中應(yīng)體現(xiàn)你由恐懼到驚喜的情感變化過程．
3．詞數(shù)90左右．開頭部分已給出，但不計入總詞數(shù)．
I had a frightening and exciting experience last Thursday night．After finishing my homework，I was going to bed．Just then，I heard the sound of footsteps outside my door．I wondered who it could be．

It couldn't be my father or my mother，because they had gone to their friend's party．They said they would come back home late．It couldn't be a thief，either．A thief would feel afraid and be very quiet．Perhaps it could be my neighbor．He may have come back home from work．He always works late in the office．I said to myself，"Be brave!There's nothing to be worried about．"Then I opened the door and all my friends were there saying"Happy birthday"．I thought they'd forgotten!How excited I was!

It couldn't be my father or my mother，because they had gone to their friend's party．They said they would come back home late．It couldn't be a thief，either．A thief would feel afraid and be very quiet．Perhaps it could be my neighbor．He may have come back home from work．He always works late in the office．I said to myself，"Be brave!There's nothing to be worried about．"Then I opened the door and all my friends were there saying"Happy birthday"．I thought they'd forgotten!How excited I was!