时间介词(at, in ,on) 的用法1. at (1)时间的一点、时刻等。如: They came home at seven o’clock。 (at night, at noon, at midnight, at ten o'clock, at daybreak, at dawn). (2)后面接表示岁数的词。 Children in China start school at 6 years old. (3)较短暂的一段时间.可指某个节日或被认为是一年中标志大事的日子。如: He went home at Christmas (at New Year, at the Spring Festival)。2. in (1)在某个较长的时间(如世纪、朝代、年、月、季节以及泛指的上午、下午或傍晚等)内。如: in 2024, in March, in spring, in the morning, in the evening, etc (2) 在一段时间之后,常用于将来时。 He will arrive in two hours. These products will be produced in a month. 3. on (1)具体的时日和一个特定的时间,如某日、某节日、星期几等.如: On Christmas Day(On May 4th), there will be a celebration. (2)在某个特定的早晨、下午或晚上。如: He arrived at 10 o'clock on the night of the 5th. (3)准时 , 按时 。如: If the train should be on time, I should reach home before dark. 表示频率的副词用法详解一、常见的频率副词always,usually,often,sometimes, seldom,never.1) always 表示的频率为 100% , 意思是”总是、一直、始终"。 I always do my cleaning on Sundays。 我总是在星期天搞卫生.2)usually 与 always 相比,表示的频率要低些,约为 70%-80%.意思是”通常". Plants are usually green。 植物通常是绿色的。 Usually she goes to work by bus. 她通常乘公共汽车去上班。 3)often 的频率比 usually 又略低些,约为 60 % -70% ,意思是"常常"、"常常”。 Do you often write to them? 你常给他们写信吗? Does Fred come here often? 弗雷德常来这儿吗? 4)sometimes 的频率比 often 又低些,约为 50%>sometimes>30%,意思是“有 时、不时”。 Jenny usually eats a sandwich for lunch. Sometimes she eats soup.5)seldom 的频率比 sometimes 还要低些约为 20 %左右 ,意思是“很少”。 My father was seldom at home on Sundays。 我父亲星期天...