So do I

When writing your essay, one very useful structure is 'So do I' and the gang. The following examples will illustrate this point.

1 He comes from a poor family. So do I.
2 Kassim liked to play kites when he was small. So did I.
3 He will join the newly-formed club. So will I.
4 She has paid the club subscription. So have I.
5 Every Chinese is celebrating Chinese New year next Monday. So am I.