根据所给首字母或汉语提示完成单词。
(1)The old s is, "Who laughs last, who laughs best!"
(2)I had a toothache, so I must go to see the (牙医).
(3)It's hard to (选择) the best answer to the question.
(4)He saw some (老鼠)in the street yesterday.
(5)My brother Jack is more (外向的)than me.