Mrs．Marks bought a printer yesterday．She was h because she could print anything she wanted at any time．H,after about an hour, she was angry because she couldn't print the color blue．All the other c printed free, except(除了)blue，which was very unusual．
She d to call the after-sales service department(售后服务部)to help her solve the problem．David answered the phone．He t everything he could think of to help Mrs．Marks．He asked her to reinstall(重新安装) the program，to reboot (重新启动)the computer and to turn the printer on and off．N of these things helped．
After hours of trying，the problem swasn't solved．Finally, David asked Mrs．Marks if he could go to her hand try to solve the problem in person．Mrs．Marks agreed and t him her address(住址)．When he arrived at her house，she showed him her computer and the printer. David uwhat the problem was right away．He told her,“From now on，print on white paper instead of blue!”
