The students were having their chemistry class.有were为什么还有having呢?

The students were very h_____ . The students were fast (sleep). Who were the students with today There were many students inThere were many students in the classroom(改为单数句) The students were listening to the teacher attetively是什么意思 The audience,（）,enyoyed the performancemost of them were studentmost of whom were studentsthey were mostly studentsthey thenselves were students All the students were here yesterday.的同义句 all the students were very excited改一般疑问句快 All the students were very excited 怎么肯定否定回答 All the students were very happy怎么改否定句 all the students were very sxcited的肯/否 all the students were very sxcited的否定句 the students were all ( ) home.选in还是at Were there any students on the playground作否定答语 All the students were bored at this filmwere bored There were many students in the libThere were many students in the library last week（改为一般疑问句） He is one of the students who（ ）invited to the meeting.A have been B Ha The teacher said that they were hard working students.那空为什么填were?