I went to the USA. 一般过去时 I didn't go to the USA. 一般过去时否定句 Did you go to the USA? 一般过去时疑问句 I did my homework. 一般过去时 Ididn't do my homework. 一般过去时否定句 Did you do your homework? 一般过去时疑问句 I was doing my homework. 过去进行时 I wasn't doing my homework 过去进行时否定句 Were you doing your homework? 过去进行时疑问句
特殊疑问句 what was he saying yesterday?他昨天说什么? 一般疑问句 were they doing their homework at that moment?他们在那时做作业了吗? 肯定句 i was finishing my homework at night.我昨天晚上写完我作业了, 否定句 she wasn't watching tv at that time. 她在那时没有看电视.