是"every three day"还是"every three days"(每三天)

问题描述:

是"every three day"还是"every three days"(每三天)

every three days每隔三天。
没有every three day这种说法。

every three days

当然是every three days拉,三天一次嘛.day是可数的名词,那3天就要用复数了咯~~~~~

every three days
every third day

应该是days 吧..
两天一上的数词天,就要加s的..
所以正确应该是:every three days(每隔两天,三天一次)