stress是可数名词吗

　　Stress at work is a matter of concern to staff and management.

　　工作压力是一件让员工和管理人员都关切的事。

　　Thinking positively is one way of dealing with stress.

　　保持乐观是对付压力的一种方法。

　　Stress is often a factor in the development of long-term sickness.

　　心理压力常常是形成长期病的一个因素。