Put in the verbs in a correct form

Passive

Translate and underline the Emphatic construction.

Emphasis

Put in the verb in a correct form from the box.

Modals

Test 4

may..may…….not able to…….can…….may…….might have been……. can…….be able to…….can…….cannot

1. Desert plants ….. have to go without fresh water for years at a time

2. Many desert plants …… live to be hundreds of years old.

3. The pounding of the soil by the hooves of livestock …… degrade the soil and encourage erosion by wind and water.

4. By 2050, a third of the people on Earth ….. lack a clean, secure source of water.

5. These areas have two seasons: a growing season and a dormant season. During the dormant season, no grass ….. grow because it is too cold.

6. Grasses ….. survive fires because they grow from the bottom instead of the top.

7. In the tropics, each canopy tree ….. release about 200 gallons (760 liters) of water each year.

8. Shrubs and spruce that previously ….. take root on the permafrost now dot the landscape, potentially altering the habitat of the native animals.

9. Many cities in developing countries in particular are growing too rapidly for their own good, with many residents …..find jobs and forced to live in slums.

10. Scientists think there ….. a cooling in the earth`s atmosphere during the Late Cretaceous Period.

1. Written in our mitochondrial DNA (mtDNA) is the story of our great ancestors – from their origins in Africa to their wondrous journeys around the world.

2. Today the animal mummies are one of the most popular exhibits in the whole treasure-filled museum. Visitors of all ages, Egyptians and foreigners, press in shoulder to shoulder to get a look. Behind glass panels lie cats wrapped in strips of linen that form diamonds, stripes, squares, and crisscrosses.

3. Can you guess what did happened? Animals moved out of the water onto the land. The first creatures that crawled out onto the swampy shore were not yet entirely of land animals. They were amphibians which is means that they had to spend some of their life in the water.

4. They had long slim bodies and well-developed tails. They had lungs with which to breathe air and legs that could support them on solid ground. They were also too good swimmers and have spent a great deal of their time in the water, eating small fish.

5. Now, whenever the droughts were very severe and some of the ponds and rivers dried up completely, many the fish died off. But the amphibians stayed alive because they could use their legs to walk to another spot where there was some water on left.

1. The bacteriophage ….. (discover) independently by the microbiologists F. W. Twort (1915) and Félix d'Hérelle (1917).

2. The phages ….. much (use) in the study of bacterial genetics and cellular control mechanisms largely because the bacterial hosts ….. so easily (grow) and …..(infect) with phage in the laboratory.

3. Phages ….. (use) in an attempt to destroy bacteria that cause epidemic diseases, but this approach ….. largely (abandon) in the 1940s when antibacterial drugs became available.

4. The possibility of "phage therapy" ….. recently (attract) new interest among medical researchers, however, owing to the increasing threat posed by drug-resistant bacteria

5. Bluebirds ….. (consider) fairly common, but their numbers have declined substantially during the last century.

6. Bird populations ….. (give) a boost by the birdhouse boxes that have become popular in many parks and backyards.

7. By the end of the Age of Fishes the land ….. (cover) with tree-fern forests.

8. Lysis can ….. readily (observe) in bacteria growing on a solid medium, where groups of lysed cells appear as clear areas.

9. The world's semi-arid regions are turning into desert at an alarming rate. This process, known as "desertification," ….. (not cause) by drought, but usually arises from the demands of human populations that settle on the semi-arid lands to grow crops and graze animals.

10. Many trees and plants, like orchids, ….. (remove) from the rain forest and cultivated.

11. Brazil nut tree ….. (pollinate) by bees that also visit orchids, and its seeds ….. (spread) by the agouti, a small tree mammal.

Дата добавления: 2014-01-04