题目
Grace Brown leads a busy school life. Apart from the many required subjects, the 14-year-old girl also sings in a choir (合唱团)and plays the piano. The school day lasts from 8 a.m. to 4 p.m., but Grace has so many activities to attend that she has no time for P. E. classes. That's why Grace has chosen to take P.E. classes on her own time. Her school has allowed her to try "virtual" P.E. . For many subjects, tests and textbooks have become available on computers. Now, new technologies are also having an effect on P.E. . Grace wears a fitness tracker (追踪设备)called Fitbit on her arm while exercising. She usually exercises three times a week for 30 minutes each time. A program on her computer records her activity. Grace How long does it take Grace to do exercise every week? A 3 minutes. B 30 minutes. C 60 minutes. D 90 minutes.
Grace Brown leads a busy school life. Apart from the many required subjects, the 14-year-old girl also sings in a choir (合唱团)and plays the piano. The school day lasts from 8 a.m. to 4 p.m., but Grace has so many activities to attend that she has no time for P.
- E. classes. That's why Grace has chosen to take P.
- E. classes on her own time.
Her school has allowed her to try "virtual" P. - E. . For many subjects, tests and textbooks have become available on computers. Now, new technologies are also having an effect on P.
- E. . Grace wears a fitness tracker (追踪设备)called Fitbit on her arm while exercising. She usually exercises three times a week for 30 minutes each time. A program on her computer records her activity. Grace How long does it take Grace to do exercise every week?
A 3 minutes.
B 30 minutes.
C 60 minutes.
D 90 minutes.
题目解答
答案
我们来一步一步分析题目，找出正确答案。
---
### 题目内容回顾：
Grace 每周锻炼 **三次**，每次锻炼 **30分钟**。
问题问的是：**Grace 每周总共花多少时间锻炼？**
---
### 解题过程：
1. **每次锻炼时间**：30分钟
2. **每周锻炼次数**：3次
3. **总时间计算**：
$ 30 \text{分钟} \times 3 = 90 \text{分钟} $
---
### 选项分析：
- A. 3分钟 → 错误，明显太短
- B. 30分钟 → 错误，这是每次的时间，不是每周
- C. 60分钟 → 错误，每周锻炼时间应为90分钟
- D. 90分钟 → **正确**
---
### 最终答案：
$$
\boxed{D}
$$