My mother used to ask me what the most important part of the

My mother used to ask me what the most important part of the body was. Through the years I would guess that what I thought was the correct answer.
When I was young, I thought sound was very important to us, so I said, “My ears, Mum.” She said, “No. Many people are deaf. But you keep thinking about it and I will ask you again soon.”
Several years passed before she asked me again. Since making my first try, I had contemplated （仔细考虑）the correct answer. So this time I told her, “Mum, sight is very important to everybody, so it must be our eyes.” She looked at me and told me, “You are learning fast, but the answer is not right because there are many people who are blind.”
Over the years, Mother kept asking me the same question and her answer was always, “No, but you are getting cleverer every year, my child.”
Then last year, my grandpa died. Everybody was hurt. Everybody was crying. My mum looked at me when it was our turn to say our final goodbye to Grandpa. She asked me, “Do you know the most important body part yet, my dear?”
I was surprised when she asked me this now. I always thought this was a game between her and me. She saw the confusion（迷惑）on my face and told me, “This question is very important. It shows how you have really lived your life.” I saw her eyes filled with tears（眼泪）. She said, “My dear, the most important body part is your shoulder.”
I asked, “Is it because it holds up your head?”
She answered, “No, it is because it can hold the head of a friend or loved one when they cry. Everybody needs a shoulder to cry on sometimes in life, my dear. I only hope that you have enough love and friends that you will have a shoulder to cry on when you need it.”
Then and there I knew the most important part of the body is not a selfish one. It is the care to the pain（痛苦） of others.
小题1: What did his mother use to ask him?________________________________________________
小题2: Did he think sound was very important to them when he was young? ______________________
小题3: When did his grandpa die? ________________________________________________________
小题4: Why is shoulder the most important part of the body? __________________________________
小题5: What did his mother want to tell him in the end? ______________________________________