閱讀下面短文，根據(jù)所給情節(jié)進行續(xù)寫，使之構成一個完整的故事。
    As I sat in the second-floor window of our schoolhouse that afternoon，my heart began to sink further with each passing car.This was a day I'd looked forward to for weeks： Miss Pace's fourth-grade，end-of-the-year party.
    I had happily volunteered my mother when Miss Pace requested cookie volunteers.But two o'clock passed，and there was no sign of her.Most of the other mothers had already come and gone，dropping off their offerings of chips and cupcakes.
    "Don't worry，Robbie，she'll be along soon，" Miss Pace said as I gazed down at the street，holding out hope that my mother would carry with a tin of her famous cookies.
    The three o'clock bell rang and I grabbed my book bag from my desk and shuffled（拖著腳步） out the door for home.
    On the four-block walk to our house，I plotted my revenge（復仇）.I would slam the front door upon entering，refuse to return her hug when she rushed over to me，and vow never to speak to her again.
    The house was empty when I arrived and I looked for a note on the refrigerator that might explain my mother's absence，but found none.My chin trembled with a mixture of heartbreak and anger.For the first time in my life，my mother had let me down.
    I was lying face-down on my bed upstairs when I heard her come through the front door.
    "Robbie，" she called out a bit urgently. "Where are you？"
    I remained silent.When she entered my room and sat beside me on my bed，I didn't move but instead stared blankly into my pillow refusing to acknowledge her presence.
    "I'm so sorry，honey，" she said. "I just forgot.I got busy and forgot--plain and simple."
    I still didn't move "Don't forgive her，" I told myself.
    Then my mother did something completely unexpected.She began to laugh.I was skeptical.How could she laugh at a time like this？I rolled over and faced her，ready to let her see the anger and disappointment in my eyes.
注意：
1．所續(xù)寫短文的詞數(shù)應為150左右；
2．至少使用5個短文中標有下劃線的關鍵詞語；
3．續(xù)寫部分分為兩段，每段的開頭語已為你寫好；
4．續(xù)寫完成后，請用下劃線標出你所使用的關鍵詞語。
    Paragraph 1：
    Surprisingly my mother wasn't laughing at all，but she was crying._____
    Paragraph 2
    "It's okay，Mom，" I stammered （結巴） as I reached out and gently touched her hair._______