Study:
一般时:1、现在study2、过去studied3、将来willstudy4、过去将来wouldstudy
进行时:1、现在studing2、过去was/werestuding3、将来willbestuding4、过去将来wouldbestuding
完成时:1、现在havestudied2、过去hadstudied3、将来willhavestudied4、过去将来wouldhavestudied
完成进行时:1、现在havebeenstudying2、过去hadbeenstudying3、将来willhavebeenstudying4、过去将来wouldhavebeenstudying