改错.下列每个句子均有一处错误,请改错.

改错.下列每个句子均有一处错误,请改错.
1.Today it’s my son's two birthday.He is two years old now.
A：it’s B：my son's C：two D：two years old
2.Don't please make a noise.They are having a meeting.
A：Don't please B：make a noise C：They are having D：a meeting
3.Computer are very powerful machine.
A：Computer B：are C：powerful D：machine
4.The invent of the zero zero people write big numbers.
A：invent B：zero C：zero D：write