[解析]
(1)What's the matter?考查文章的理解和上下文的联系,可知此处应该是:怎么了?
故填What's the matter.
(2)How long have you been like this?考查文章的理解和上下文的联系,可知此处应该是:你这样多久了.
(3)I think so.考查文章的理解和上下文的联系,可知此处应该是:我认为是这样.
(4)What can I do then?考查文章的理解和上下文的联系,你最好不要出去,多喝水和你会没事?故填What can I do then.
(5)I will.Thanks 考查文章的理解和上下文的联系,谢谢.Thanks.