Es.1 pag. 235

1. Michael never drinks beer. Beer is never drunk by Michael.

2. We have just booked our summer holidays. Our summer holidays have just been booked by us.

3. Rachel sent some texts two days ago. Some texts were sent by Rachel two days ago.

4. When I arrived, he had already broken the mirror. When I arrived, the mirror had already been broken by him.

 5.  Farmers grow vegetables. Vegetables are grown by farmers.

6. Don’t worry. I’ll call him straight away! Don’t worry. He will be called by me straight away!

7. Somebody has just seen a ghost in the castle. A ghost has just been seen by somebody in the castle.

8. Shakespeare wrote more than 30 plays. More than 30 plays were written by Shakespeare.

Es.2 page. 235

For the first step, natural ingredients such as flowers, fruit and wood are harvested from around the world.

Alcohol, petrochemicals and other chemical substances are also used in the manufacture of perfumes. Not

every plant contains essential oils; oils aren’t produced naturally by, for example, lily of the valley flowers.

In the next step, the oil is extracted. This is done immediately after picking. Solvent extraction is a common

method. To extract oils from roses, layers of petals are placed on a metal-layered drum.

The flowers are then immersed in a solvent. The result of this process is a waxy material that contains the

oil, which is then washed in ethyl alcohol. The oil is dissolved in the alcohol and rises. Other extraction

methods include steam distillation, enfleurage and maceration. A huge number of plants are needed to get

a small amount of essential oil. Approximately 200,000 rose flowers, that is 400 kilograms of flowers are

required to make 600 grams of essential oil. Once the essential oil is ready, it is blended together according

to a certain formula and then it is mixed with alcohol. It may take as many as 800 different ingredients and

several years to develop the special formula for a scent. In the last step of the process, the perfume is aged

for several months or even years after it is blended.

Es. 3 pag. 395

Olive oil is produced by grinding olives and extracting the oil by mechanical or chemical means.

The olives are ground into paste using large millstones or steel drums.

If ground with millstones, the olive paste generally stays under the stones for 30 to 40 minutes. After grinding, the olive paste is spread on fiber disks, which are stacked on top of each other in a column, then placed into the press. Pressure is then applied onto the column to separate the vegetal liquid from the paste. This very slow separation process has been replaced by centrifugation, which is much faster and more thorough. The centrifuges have one exit for the watery part and one for the oil.

In modern steel drum mills the grinding process takes about 20 minutes. After grinding, the paste is stirred slowly for another 20 to 30 minutes in a particular container where the microscopic oil drops unite into bigger drops, which facilitates the mechanical extraction. The paste is then pressed by centrifugation and the water is thereafter separated from the oil in a second centrifugation as described before.

Es. 4 pag. 395

1. We got there late and the birthday cake had already been served.
2. Is there anybody here who knows when the Tower of London was built?
3. Some of these paintings have been lent by a private collector.
4. If it stops snowing tomorrow, the roads will be cleared.
5. The ticket that won the first prize in the lottery was bought last week near Rome.
6. Yesterday the alarm of a car that had been parked near ours rang for more than two hours!

Es. 5 pag. 395

1. The car is washed by David every Saturday. The car isn’t washed by David every Saturday. Is the car washed by David every Saturday?
2. The film has been seen by lots of teenagers. The film hasn’t been seen by lots of teenagers. Has the film been seen by a lots of teenagers?
3. The children were helped by an elderly lady. The children weren’t helped by an elderly lady. Were the children helped by an elderly lady?
4. That bridge had been built just the year before. That bridge hadn’t been built just the year before. Had the bridge been built just the year before?
5. A ghost has been seen here. A ghost hasn’t been seen here. Has the ghost been seen here?
6. The meeting will be put off. The meeting won’t be put off. Will the meeting be put off?