Question

It was a good day. (改为一般疑问句,并作肯否回答)？

Answer 1

Was it a good day?
Yes ,it was./No,it wasn't .
改成疑问句，一般是把be 动词提前，其余成分照抄；
含有be动词的句子改否定句就是在be动词后面加not

Answer 2

Was it a good day?
Yes,it was.
希望以上的回答可以帮助到你。