Write the sentences using personal and impersonal constructions.
1 Experts believe that they will have renovated the clock
tower by the end of the year.
The clock tower ...
It is believed
2 They say that the Salisbury Cathedral clock in England is
the oldest working clock.
The Salisbury Cathedral clock in England
It
...
3 They estimate that the oldest timekeeping device is a
sundial from Egypt that dates back to 1500 BC.
A sundial from Egypt that dates back to 1500 BC
it
4 Some people think that time travel is possible.
Time travel
It
5 They say that the 3D Quantum Gas Atomic Clock is the
most precise clock in the world.
The 3D Quantum Gas Atomic Clock...
It ..