I'm not feeling well. I have ___.
我不舒服。我___。
表达身体不适,后接 fever/headache/stomach pain 等症状
What seems to be the problem?
哪里不舒服?
医生问诊开场白,也是问别人状况的礼貌用语
How often should I take ___?
___多久吃一次?
问用药频率,take 换成 use 也可
Drink plenty of water.
多喝水。
最实用的健康建议,也可说 Get plenty of rest