Bobby walked on the sidewalk. He walked past the park. He saw the kids playing. "Why don't they want to play with me ?” he thought.
It was a mystery（谜）to him. Oh , sure. He was new in town . They moved to the town just two months ago. He knew it was hard to make new friends .
At the same time , Cassie watched Bobby from the park. Every day she saw this boy walk by slowly .
     " Why doesn't he want to play with us?" she thought. Oh, sure. He was new in town. But she'd tried to say "Hi" to him. It was a mystery to her.
The days went on. Bobby walked to and from school alone. He always felt bad about not having friends. Cassie kept saying" Hi" but they never talked more.
Bobby kept thinking about it.      Finally , three weeks before the end of school , Cassie had an idea. "I'm not sure why he doesn't seem to want friends..         I'm going to invite him to my birthday party. " Cassie wrote an invitation to invite Bobby to her birthday party.
"Will Bobby come to my birthday party?" she was not sure, It was still a mystery to her.

A. He never stopped. B. He is so crazy. C. But I am going to try harder. D. But he still didn't understand. E. Cassie kept thinking about it. F. I'm not interested in playing it. G. What was the problem?