应该填can you pass.因为if引导的是条件状语从句,Only if开头的时候,在主句中需部分倒装.
本题考的是倒装句.当“Only+状语”放在句首时,句子需要部分倒装.例如：
Only in this way can you solve the problem.(句中in this way为方式状语）
The river has been polluted,but only recently have the harmful effect been known.(句中recently为时间状语）
Only after the war did the lady know the truth.（句中after the war为时间状语）