?在周末

... on Sunday(在星期天), on weekends(在周末), on February 8th(在二月八日), ...

?每逢周末

Stop doing sth 停止做某事 stop to do sth 停下来做某事 on weekends 每逢周末 Young people need to sleep. 年轻人需要睡眠 need to do sth 需要做某事 .

?在每个周末

... at the weekend 〈英〉在周末(假期里) during the weekend 〈美〉在周末(假期里) on weekends 在每个周末 ...

?周末

... 导游；刷净；练习 exercise （在）周末 on weekends 最好的；一般地 usually ...