1、The students do their homework every day.Now they are doin

1、The students do their homework every day.Now they are doing their homework.中The students do,为什么是do,而不是does?
2、—What are the students doing?
—Some are reading and others are looking at the blackboard.
为什么是reading和looking,而不是reading和watching?
3、at,in,on 在英语时间中怎么放?

1.students 是student 的复数形式,作主语时动词用原型,所以用do.（does 是do的第三人称单数形式.）
2.read 是指看的状态,说明他们一直都在读书；而look 多指看的动作,watch 一般指全神贯注地看,如看电视,看比赛等等.
3.at 用于具体的时间前（如 在七点,at 7 o'clock）,
on 用于具体的某一天前（如 在星期天 on sunday）,
in 用于月份和年份前（如 在4月 in apirl,在1999年,in 1999）