Severe stress or certain illnesses also can delay menstruation .

巨大的压力或某些疾病也会使经期推迟。

These are common childhood illnesses all over the world .

它们在全球都是常见的儿童传染病。

What illnesses often co-exist with depression ?

哪些疾病常与抑郁症共存？

Measles is the most serious of the three illnesses .

麻疹是这三种疾病中最严重的一种。

Symptoms are subtle and easily confused with other illnesses .

相关症状并不明显，且容易与其它疾病混淆。