unless otherwise agreed

例句：

1. 1. You must finishyour homework before you go to bed.
   你必须在你上床睡觉之前完成你的作业。
2. 2. Unless you have a valid passport, youcannot enter the country.
   除非你有有效的护照，否则你不能进入这个国家。
3. 3. Unless you are careful,you might fall off the ladder.
   除非你小心，否则你可能从梯子上摔下来。