a. This is the second time they have written to us about this.
=>This is the second time this has been written to us.
b.Mr.Smith has taught us French for 2 years.
=>We have been taught French by Mr Smith for 2 years
c.They didn't look after the children properly.
=>The children weren't looked after properly.
d.We import these machines from the USA
=> These machines are imported from the USA.
e.Nobody swept this street last week.
=>This street wasn't swept last week