Пасивний стан дієслів

Open the brackets using Present or Past Passive

1. The theory of relativity ….(to develop) by Albert Einstein.

2. Sand clocks …(to use) in the Middle Ages.

3. Yoghurt… (to make) from milk.

4. The stuff… (to instruct) be the manager.

5. The Great Pyramids …( to visit) by thousands of tourists every year.

 6.Volkswagens cars…( to produce) in Germany.