Which day is the most important for you? Your birthday, the first day of your work or the day you win a prize. Many teenagers may think their birthday is the happiest time because they can receive many wonderful presents and have much fun with their friends. Others may regard the starting day of their work as the most meaningful. They think it's the first big step in their life and they can depend on themselves. They like to deal with challenges rather than to ask for the help of adults. According to a survey, more than half of the Chinese people, certain ages and birthdays are especially important. One hundred days after a baby's birth has special meaning. On that day, relatives  and friends come to bless the baby. In northern part of China, like Inner Mongolia, a child's 12th birthday is a big day. This is when a child becomes a teenager. Eighteen is another important age, which means you must be responsible  for what you have done in laws. As for adults, maybe the anniversary of their marriage  is the most important. For some old people, the 60th or 70th birthday is also very important. They like to be cared about by all his family and friends, and the big family get-together can provide them a good chance to recall  the past. When you are   _  years old, you must be responsible for what you have done in laws.
12 18 20 60