简述合同解除与附解除条件的区别。

     On August 26, 1999, New York City was struck by a terrible rainstorm. The rain caused the streets   1   
and the subway system almost came to a stop.
     Unfortunately, this happened during the morning rush hour. Many people who were going to work were
   2    to go home. Some battled to   3   a taxi or to get on a bus. Still others faced the   4   bravely, walking
miles to get to work.
     I   5   to be one of people on the way to work that morning. I went from subway line to subway line only
 to find that most   6   had stopped. After making my way   7   crowds of people. I finally found a subway
line that was   8  . Unfortunately, there were so many people waiting to   9   the subway that I could not even
get down the stairs to the  10 . So I took the train going in the opposite direction, and then switched back to
the downtown train. Finally, after what seemed like forever, the train  11  my stop. Then I had to walk several
blocks in the increasingly heavy rain. When I got to my office, I was  12  through, exhausted and  13 .
     My co-workers and I spend most of the day drying off. When it was 5:00 pm, I was ready to go home. I
was about to turn off my computer  14  I received an email from Garth, my Director:
     I would like to thank all of you who made the effort and  15  reported to work. It is always reassuring (令
人欣慰), at times like these, when employees so clearly show their  16  to their jobs. Thank you.
     Garth's email was short, but I learned more from that  17  message than I ever did from a textbook. The
email taught me that a few words of  18  can make a big difference. The rainstorm and the traffic  19  had
made me tired and upset. But Garth's words immediately  20  me and put a smile back on my face.