My teenage son Karl became withdrawn after his father died. As a single parent, I tried to do my best to talk to him. But the more I tried, the more he pulled away. When his report card arrived during his junior year, it said that he had been absent 95 times from classes and had six falling grades for the year. In this way he would never graduate. I sent him to the school adviser, and I even begged him. Nothing worked.
One night I felt so powerless that I got down on my knees and asked God for help. “Please God, I can’t do anything more for my son. I’m at the end of my rope. I’m giving the whole thing up to you.”
I was at work when I got a phone call. A man introduced himself as the headmaster. “I want to talk to you about Karl’s absences.” Before he could say another word, I choked up（哽咽）and all my disappointment and sadness over Karl came pouring out into the ears of this stranger. “I love my son, but I just don’t know what to do. I’ve tried everything to get Karl to go back to school and nothing has worked. It’s out of my hands. ” For a moment there was silence on the other and of the line. The headmaster seriously said, “Thank you for your time”, and hung up.
　　Karl’s next report card showed a marked improvement in his grades. Finally, he was even on the list of the best students at school. In his fourth year, I attended a parent –– teacher meeting with Karl. I noticed that his teachers were surprised at the way he had turned himself around. On our way home, he said, “Mum, remember that call from the headmaster last year?” I nodded. “That was me. I thought I’d play a joke but when I heard what you said, it really hit me how much I was hurting you. That’s when I knew I had to make you proud.”
Which of the following has the similar meaning as the underlined word “withdrawn” in the  first paragraph?

A．preferred to stay alone at home

B．refused to go to school

C．refused to talk to others

D．began to dislike his mother

There was silence on the other end of the line because _ _________.

A．the caller was too moved to say anything to the mother

B．the caller waited for the mother to finish speaking

C．the caller didn’t want the mother to continue her talk

D．the caller was unable to help the mother

Who was it that telephoned Karl’s mother that day?

A．The headmaster.	B．The school adviser.
C．Karl himself.	D．The passage doesn’t tell us.

From the passage we can learn that _____________.

A．children in single – parent families always have mental problems

B．mother’s love plays an important role in teenagers’ life

C．parents should give their children as much help as possible

D．school education still works well without support from parents