疾病只有一种解释吗？答案当然是No，下面我们就一起看看吧。
1.ailment
1.1-常指小病
1.2-
eg:
childhood/common/minor ailment
2.sickness
2.1-相对严重的病，会影响平常生活
2.2-
eg:
she has been off work because of sickness.
3.disease
3.1-约等于sickness,但是常指可以传染的病
3.2-
eg:
heart/kidney/liver disease.
4.illness
4.1-除了身体还可以精神上的疾病
4.2-
eg:
mental illness.
