根据短文理解，从A、B、C、D四个选项中选择最佳的一个答案填空。
Sometimes, I want to know whether there is any love between my parents. Every day, they are 1 trying to make money. They don't act romantically（浪漫地）the way couples(夫妇)do in books 2 on TV. They never say “I love you" to each other. It's not their 3.
One day, my mother was sewing(缝) a quilt. I sat down next to 4. “Mom, I have a question to ask you," I said after a while. “What?" she asked, still working.
“Is there love 5 you and Dad?” I asked her in a very low 6.
She stopped her work and 7 her head. Then she bowed（低下）her head and went on sewing.
I thought I had hurt her. At last I heard my mother say, “Susan, look at this thread（线）Sometimes it 8, but most of it disappears in the quilt. It makes the quilt 9. If life 10 a quilt, then love should be a thread. It can 11 be seen anywhere, but it's really there.”
I listened carefully but I didn't understand her 12 the next spring. My father suddenly got sick. My mother had to stay with him in the 13 for a month.
After they got back, she helped my father walk slowly down the road every day. My father had never been so weak.
“Dad, 14 are you feeling now?" I asked him one day.
“Susan, don't worry about me,” he said gently “I just like 15 with your mom.” Once I thought love meant flowers, gifts and sweet kisses. Now, I know that love is the thread that holds a family together.