题目内容：
Physical fatigue is usually caused by __________．
A．transmittable diseases B．too many stimulants
C．lack of physical exercise
D．excess wastes in the bloodstream
参考答案：
答案解析：
单选题：Physical fatigue is usually caused by __________．
- 题目分类：英语六级
- 题目类型：单选题
- 号外号外：注册会员即送体验阅读点！
B．too many stimulants
C．lack of physical exercise
D．excess wastes in the bloodstream