都可以不用加：
1.They planned to barrel the beer next Monday.
他们打算下星期一把啤酒装桶.《21世纪大英汉词典》
2.The rest of the questions have stood over till next Monday.
其余的问题已延期至下星期一进行讨论.《21世纪大英汉词典》
3.I agreed to speak at an international conference in Shanghai next Monday.
我答应下星期一在上海的一个国际性大会上讲话.
1.Last Sunday I saw an unpleasant thing in the park.
上周日在公园里我看见一件不愉快的事.
2.Last Sunday they reached Nanjing,where a conference was to be held.
他们上周日到达南京,有个会议要在那里举行.
3.Last Sunday,I experienced another first in a restaurant near our apartment.
上周日,我在公寓附近经历了另一项在餐厅里发生的第一次.
one other day 是“其他的一天”；
one more day 是“再多一天 ”