Question

【题目】The young trees ______ every three days.
A.are watered
B.were watered
C.are watering
D.have watered

Answer 1

【答案】A
【解析】句意：这些小树每三天被浇一次水。主语trees与water之间构成动宾关系；every three days可知时态为一般现在时。故选A。