X. A) 76. lovely 77. eleventh 78. countries 79. introduce 80. hers

　　B) 81. moon 82. usually 83. tired 84. chemistry 85. save

XI. One possible version

　　Hi Robert,

　　We had a graduation party last Sunday. Long before 3:00 pm, all the s

　　tudents in my class couldn’t wait to come to the hall. Our teachers and parents were invited to the party, too. First, our monitor made a speech. He thanked our teachers and parents sincerely. Next, we gave presents to each other. The most exciting moment was the show time. We sang, danced and played games. Our English teacher told a story which made us all laugh. Everyone was so happy. I think the wonderful party will always be in my mind.

　　Do you have such a party? Please write soon.

　　Yours, Li Ming