问题补充:
These plants are watered __ .
A. every a few days
B. every third day
C. every others day
D. each two days
答案:
A. every a few days
(答案→)B. every third day
C. every others day
D. each two days
解析:短语:每几天every few days, few前不能加a,每两天every two days/ every other day,每三天every three days/ every third day,从四个选项中看出只有B表达正确。