写出下列动词过去式spend,ask,study,is,go,play,watch,stay,visit,clean,have,cook,read,write,looksit,practice,isn'tsit,practice,isn't哪

　　写出下列动词过去式spend,ask,study,is,go,play,watch,stay,visit,clean,have,cook,read,write,look

　　sit,practice,isn't

　　sit,practice,isn't哪