sometimes后面接动词always、sometimes、seldom、never、usually等，如果这些词前面（主语）是第三人称的话，那么后面的动词要加s，如果这些词前面是第一人称的话，那么后面的动词要用原形。
sometimes例句
1.Students sometimes do casual work in the tourist trade.
学生有时做些旅游方面的零工。
2.Young children are beginning their formal education sometimes as early as four years old.
幼儿有时早在四岁时就开始接受正规教育。
3.I like to be on my own sometimes.
有时候我喜欢一个人待着。
4.It is sometimes possible to arrest or reverse the disease.
有时可以阻止病情发展或使病情彻底好转。
5.Teachers sometimes presuppose a fairly high level of knowledge by the students.
教师有时候假定学生的知识水平相当高。