and/or为何连用AccordingtotheNationalInstitutesofHealth,symptomsofdepressioninclude:persistentsadoranxiousfeelings;feelingsofhopelessness（and/or）pessimism;feelingsofguilt,worthlessness（and/or）helplessness;

Question

and/or为何连用
According to the National Institutes of Health,symptoms of depression include:persistent sad or anxious feelings; feelings of hopelessness （and/or ）pessimism; feelings of guilt,worthlessness （and/or ）helplessness;

Answer 1

这里指抑郁症的表现.用and表示两种病情都有,用or表示可能有其中的一种病情.比如感觉到无望,或者悲观；或者同时感觉到无望和悲观.