阅读下列短文，从每题所给的四个选项（A、B、C和D）中，选出最佳选项，并在答题卡上将该项涂黑。
A
One evening I went out and left my 17-year-old son in charge of his 8-year-old brother
and 4-year-old sister.On this occasion,the work was made less troublesome by the presence
of his girlfriend.I left with complete confidence that the older children would do a
wonderful job of babysitting the younger children.Later,I discovered that complete
confidence was the last thing I should have left home with.
I had decided to return home earlier than planned so that my son and his girlfriend
could go out.I called home with this happy news.But instead of hearing his cheerful,
