张某,男,13岁,恒牙。第一磨牙近中关系,上下牙列Ⅲ度拥挤,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

杜某,男,4岁,乳牙。乳磨牙近中关系,前牙反,下颌前伸,位置前移。

如果设计上颌垫活动矫治器矫治,垫的高度应使前牙打开

A:0mm B:0.5~1mm C:1~2mm D:2~3mm E:3~4mm

杜某,男,4岁,乳牙。乳磨牙近中关系,前牙反,下颌前伸,位置前移。

解除后,双侧垫每次应磨除

A:0.5mm以内 B:0.5~1.0mm C:0~2.0mm D:1/3 E:1/2

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. (路里),小卡,大卡

  Quit / kwɪt / v. 停止,放

  注释:

  1. ... made the decision to run across .........决正跑步横跨......

In the middle of the day: the men usually stopped running.

A:Right B:Wrong C:mentioned

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. (路里),小卡,大卡

  Quit / kwɪt / v. 停止,放

  注释:

  1. ... made the decision to run across .........决正跑步横跨......

They sometimes felt sick because it was so hot.

A:Right B:Wrong C:mentioned

我国的交流电频率是60Hz。

指针式万用表测量交流电压,只在()频率范围内测量的精度才符合要求。

A:45~1000Hz B:50~60Hz C:0~60Hz

下列对列车电源AC230V 50Hz和AC230V 60Hz的出处设备和设备输入电压叙述正确的是()

A:AC230V 50Hz来自逆变器 B:逆变器输入电压为DC110v C:AC230V 60Hz来自列车小变压器 D:变压器输入电压为AC440V 60Hz

某厂进口设备中有1台额定频率F=60Hz的三相异步电动机,其额定转速为1650r/min,现要使用额定频率为50Hz的交流三相电源,试计算有关参数。
这台额定频率为60Hz的三相异步电动机的同步速n0为( )r/min。

A:3000 B:900 C:1500 D:1800

某厂进口设备中有1台额定频率F=60Hz的三相异步电动机,其额定转速为1650r/min,现要使用额定频率为50Hz的交流三相电源,试计算有关参数。
该异步电动机运行在频率为60Hz交流三相电源时转差率为( )。

A:0.091 B:0.083 C:0.917 D:0.056

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