1.

It is essential that this door is kept unlocked.

should

On no locked.

2.

It seems unbelievable that this jewellery is almost a thousand years old when it is so well preserved.

hard

This jewellery is in such good believe that it is almost a thousand years old.

3.

When it comes to punctuality, Marie really takes after her mother.

concerned

As , Fiona really takes after her mother.

4.

You have to be very patient to work as a primary school teacher these days.

deal

Working as a primary school teacher calls these days.

5.

He didn't understand exactly what was wrong until he read Julie's letter.

only

It he read Julie's letter that he understood exactly what was wrong.

6.

None of the other team members supported Terry's idea.

support

Terry's idea met with the other members of the team.

7.

The region is rich in natural resources.

offer

The region has a lot terms of natural resources.

8.

Because of its price, the book may never become a bestseller.

prevent

The price of the book may a bestseller.
The price of the book may a bestseller.