完形填空：
67-71 ADABD
72-76 CBABD
77-81 AADCB
82-86 ADBCA
翻译答案:
87. that they have no solutions so far.
88. what most parents are concerned about.
89. in case it is getting colder
90. decided to start their own business.
91. until a doctor discovered it by accident.