他们沿校墙挖沟.They dug a dike along walls of the school.挖沟以排水.Dig trenches to drain away the water.他们挖沟以阻止森林大火蔓延.They dug trenches to keep the forest fire from spreading....
其中必有隐情.There must be something behind it.玛丽的拒绝另有隐情, 我想她是在力图隐瞒什么东西.There's more in Mary's refusal than meets the eye; I think she's trying to hide something.背后定有隐情.There must be something behind....