张某，男，13岁，恒牙。第一磨牙近中关系，上下牙列Ⅲ度拥挤,反，颊向。

骨性前牙反的临床诊断标准不包括

A:近中磨牙关系，下颌不能后退至前牙对刃 B:ANB角小于0°Ⅲ类骨面形(恒牙期) C:替牙期ANB角小于2° D:恒牙期ANB角小于3° E:伴有不同程度的颌骨大小、形态和位置异常

Across the Deserts

　　The SaharaDesertis the largest desert in the world. It stretches across Africa fromSenegaltoEgypt. TheSaharaDesertis an unfriendly environment. During the day it"s very hot, and at night it’s sometimes very cold. It is also difficult to find water in theSahara.

　　In 2006, Kevin Lin, Ray Zahab, and Charlie Engle decided to do something very difficult. They made the decision to run across the Sahara Desert 4,300 miles (6,920km). It seemed impossible to do, but they wanted to try. The three men liked to test themselves, and this would be a very big test.

　　On the morning of November 2, Kevin, Ray, and Charlie started their trip across theSahara. Every morning they began running at 5:00. At11 a.m. they stopped and rested until 5 p.m. Then they ran again until 9:30 in the evening. Each day they ran about 40 miles (64 km). Every day it was the same thing. They got up and ran. They listened to music on their iPods, and they ran and ran.

　　Kevin, Ray, and Charlie needed to eat a lot of food during their trip. Most people need about 2,000 calories of food each day. Kevin, Ray, and Charlie needed between 6,000 and 9,000 calories every day. That"s a lot of food! They also needed to drink a lot of water.

　　The three men had some problems on their trip, and many times they wanted to quit and go home. It was often very hot (140°F/60°C) during the day, and the heat made them sick. Their legs and feet hurt. Sometimes it was very windy, and they couldn"t see. One time they got lost. But they didn"t quit. After 111 days, Kevin, Ray; and Charlie successfully finished their trip across theSaharaDesert. They hugged each other and put their hands in the water of theRed Sea. Then they ran to a hotel to take a long shower.

　　词汇：

　　Stretch / strɛtʃ / v. 延伸，伸展

　　Calorie / "kælərɪ / n. 卡(路里)，小卡，大卡

　　Quit / kwɪt / v. 停止，放

　　注释：

Each day the men ran for approximately eight hours.

A:Right B:Wrong C:mentioned

当寄存器PSW的RS0和RS1分别为1和0时，系统选用的工作寄存器组为（）

A:组0 B:组1 C:组2 D:组3

若RS1=1，RS0=0，选中的工作寄存器组是第（）组。

工作寄存器区的选择位RS1、RS0在（）特殊功能寄存器中。

当程序状态字寄存器PSW状态字中RS1和RS0分别为0和1时，系统使用的工作寄存器组为（）。

A:组0 B:组1 C:组2 D:组3

在8051单片机中，当RS1和RS0为11B时工作寄存器位于内部RAM的（）区域内。

A:00-07H B:08H-0FH C:10H-17H D:18H-1FH

在8051单片机中，当RS1和RS0的值为01B时工作寄存器位于内部RAM的（）区域内。

A:00-07H B:08H-0FH C:10H-17H D:18H-1FH

在8051单片机中，当RS1和RS0为10B时工作寄存器位于内部RAM的（）区域内。

A:00-07H B:08H-0FH C:10H-17H D:18H-1FH

80C51有四个工作寄存器区，由PSW状态字中的RS1和RS0两位的状态来决定，单片机复位后，若执行SETBRS0指令，此时只能使用（）的工作寄存器。

A:0区 B:1区 C:2区 D:3区