单选题 .  Dad had a black comb. He bought it when he married Mum. Every night, he would     1    me his comb and say, "Good girl, help Daddy clean it. OK?"
    I was     2    to do it. At the age of five, this dull task brought me such     3    . I would excitedly turn the tap     4    and brush the comb carefully. Satisfied that I'd done a good job, I would happily return the comb to Dad. He     5    affectionately at me and place the comb in his wallet.
    Two years later, Dad started his own     6    , which wasn't doing well. That was when things started to     7    . Dad didn't come home as early and as much as he used to. Mum and I became     8    at him for placing our family in trouble.     9    time went by, an uncomfortable silence grew between us.
    After my graduation from college, Dad's business was getting back on track. On my 24th birthday, Dad came home     10    As usual, I helped him carry his bags into his study. When I turned to leave    he said, "Hey, would you help me     11    my comb?" I looked at him for a while, then     12    the comb and headed to the sink.
    It hit me then: why, as a child,     13    Dad clean his comb was such a pleasure. That routine (习惯) told me Dad was home early     14    the evening with Mum and me. It     15    a happy and loving family.
    I passed the clean comb back to Dad. He smiled at me and     16    placed the comb in his wallet. But this time, I noticed something     17    . Dad had aged. He had wrinkles next to his eyes when he smiled,     18    his smile was still as     19    as before, the smile of a father who just wanted a good     20    for his family.1.