Did you swim across the river last week?为什么不用现在完成时?

Did you swim across the river last week?为什么不用现在完成时? Did you swim across the river Have you swam across the river He swam across the river last year.为什么用across swim across the river还是swim cross the river? I can swim across the river.为什么用across而不是cross? I won't allow you to swim across the river,even if you----do Did you __ the math match last last week? Hao long did you swim?(改成现在完成时) 1、Can you swim （ ） the river A.through B.across C.to D.betwe DId you enjoy_____ (swim) in the last summer The children swim across the river 改为一般将来时 swim ( ) the river 是填across还是through?