1-5 ABCCA 6-10 BCACB 11-15 ACABB 16-20 CBBAC
21-25 BDCCA 26-30 DABAC
31-35 DCADB 36-40 ACDBA
41-45 CADBB 46-50 CDABC
51-55 ACBDD 56-60 ADABC
61-65 BCDAA 66-70 DCBAA
71-80 (One possible version)
71. computers 72. consist
73. application(s) 74. widely 75. Benefits 76. save 77. Fewer 78. development 79. started / began 80. Devices
书面表达（One possible version）
Smiling is the most beautiful universal language and like the shining gold in life, it always conveys happiness and kindness.
There are many advantages of smiling. It can not only make us happy, but also benefit our health. As is reported, people who like smiling are more likely to live longer. Besides, if we often smile at others, we may leave a good impression on them. Therefore, it can help us build up a harmonious relationship with people around us.
In my life, I would like to smile at my parents first because they have given me life and taken all the trouble to bring me up. With their care and help, I can grow up healthily and become a happy individual. Then I will smile to myself. Only in this way can I become more confident and live a better life. I will also greet every day with a smile because I believe if I smile to life, it will also smile back to me.