主句用现在完成时态,从句可以用现在时态中的：一般现在时态、现在进行时态
例子一：
when he gets to school ,the class has already begun.
例子二,when i am trying to work out the problem,he has already done it我想问一下在宾语从句中，主句用现在完成时，从句用什么一般情况下，用一般现在时态。he says that he has finished his novel但是现在进行完成时态也是可以的。如 he has been saying that he has finished his novel。