在英语中，介词是连接名词或代词（称为介词宾语）和句子其他部分的词。

它们通常用于表达时间、地点、方向、原因等关系。以下是一些常见的介词及其用法：

1. at - 表示具体的时间点、地点或年龄： e.g., I will meet you at 5 o'clock. (我在5点钟见你) e.g., She lives at No. 35, Main Street. (她住在主街35号) e.g., He is at the age of 20. (他20岁)

2. on - 表示具体的日期、星期或特定的一天： e.g., My birthday is on the 15th of June. (我的生日是6月15日) e.g., We have a meeting on Monday. (我们周一有个会议) e.g., She likes to sleep on weekends. (她喜欢在周末睡觉)

3. in - 表示一段时间、月份、季节或年份： e.g., I will be back in a week. (我一周后回来) e.g., She was born in July. (她出生在7月) e.g., They plan to travel in spring. (他们计划在春天旅行) e.g., The company was founded in 2008. (该公司成立于2008年)

4. by - 表示到某个时间点之前、通过某种方式或方法： e.g., You must finish the work by tomorrow. (你必须在明天之前完成工作) e.g., I usually go to school by bus. (我通常乘公交车上学)

5. with - 表示使用某种工具、手段或与某人一起： e.g., She cut the cake with a knife. (她用刀切蛋糕) e.g., Can you come to the party with me? (你能和我一起去派对吗？)记住这些基本的介词搭配可以帮助你在写作和口语中更准确地表达意思。