题干

心电图仪(如图所示)通过一系列的传感手段,可将与人心跳对应的生物电流情况记录在匀速运动的坐标纸上.医生通过心电图,可以了解到被检者心跳的情况,例如,测量相邻两波峰的时间间隔,便可计算出1min内心脏跳动的次数(即心率).同一台心电图仪正常工作时测得待检者甲、乙的心电图分别如图甲、乙所示.若医生测量时记下被检者甲的心率为60次/min.则:乙的心率为多少次每分钟?(   )

A:60

B:65

C:70

D:75

上一题 下一题 0.0难度 选择题 更新时间:2010-05-18 11:20:25

答案(点此获取答案解析)

D

同类题3

阅读理解

Beijing Imperial Court Food

    Imperial Court Food(宫廷菜) is a style of food with origins in the Imperial Palace and it is well-known for the original features of the raw materials and carefully selected ingredients(原料). In addition, the dishes are decorated with different colored vegetables and fruits in various shapes. Each dish has a special name, such as Yu Feng Huan Chao. And some of them even have short stories. Today, Imperial Court Food has become an important school of Chinese cooking with several places offering this special taste. While expensive, it is worth trying.

    Restaurants of Imperial Court Food

    Fangshan Restaurant

    Fangshan Restaurant is the most famous one offering the first-class Imperial Court Food. The restaurant is made up of three parts and it can hold 500 people eating at the same time. It is decorated in imperial style with the design of dragon and phoenix. Here is the best place to experience the life of the Chinese emperors in former days. Now, it serves nearly 800 kinds of Imperial Court Dishes. Among them, Man-Han Banquet is the most famous.

    Li Jia Cai Restaurant

    The dinner here is served by set menu starting at ¥298/person. That is to say, a guest cannot order a dish but a set of dishes. There are no chemicals in the dishes and all tastes are natural. This restaurant has welcomed many famous people including Bill Gates, the former premier of Britain, John Major, and Chinese superstar Jackie Chan.

    Yushan Restaurant

    The layout of the restaurant follows the imperial palace. When eating in the restaurant, diners are served by waitresses in traditional imperial clothes.

    Da Zhai Men

    The dishes and snacks cooked in this restaurant are worthy to have a try. And, the traditional performances at night is one of the restaurant's attractions.

    Royal Palace

    Both of the food and service of this restaurant are so good. You can also enjoy some wonderful performances in this large courtyard.