Open Library - открытая библиотека учебной информации

Открытая библиотека для школьников и студентов. Лекции, конспекты и учебные материалы по всем научным направлениям.

Категории

Биология Complete the questions to the text and answer them.
просмотров - 415

Exercises

Complete the sentences with the verb in the correct form: Present Simple or Present Continuous Tense.

WHAT DRAGONFLIES SEE - AND HOW

1) Dragonflies …( help) scientists to learn more about how animals and humans …(see). These insects are especially favorable for such studies because of their huge eyes with large cellular components. They …(study) the eyes of adults and nymph dragonflies for their sensitivity to light and their ability to discriminate different colors.

Insects …(have) both simple eyes and large compound eyes with thousands of separate transparent facets. Under each facet …(be) a cluster of light-sensitive receptor cells, like the retinal rods or cones of the vertebrate eye. The eye of the dragon-fly …(have) more of these facets - from 10,000 to 20,000 in each compound eye - than any other insect. The dragonfly's different eyes, and different regions of the same eye, …(contain) different combinations of receptor cells.

Three simple eyes (ocelli), which …(remain) from the nymph stage, are most sensitive to ultraviolet light and blue-green light. In contrast, the dorsal (upper) part of the adult's compound eye …(be) most sensitive to violet light; the ventral (lower) part of the same eye …(be) most sensitive to ultraviolet, blue-green and yellow. While the dragonfly …( fly), the dragonfly depends largely on the ventral part of each compound eye, which …(cover) the terrain in front, to both sides and down.

Incidentally, the dragonfly …(spend) its entire adult life in the air. These insects …(be) so modified for a flying life that they can no longer walk. They …(capture) their food, …(recognize) their mates, and even …(drop) their eggs onto the water while flying.

7) Why … dragonflies … interesting … scientists?

8) What type of eyes … … have?

9) How many facets … … have?

10) Which … … most sensitive … ultraviolet light?

11) Which … … most sensitive … violet light?

12) How … … see?

13) How much time … … … …. the air?

14) Can … walk?

15) What … … … while flying?

Fill in the gaps with the verb in the correct form: Present Simple or Present Continuous Tense.

2) The heart ………..(pump) blood through the circulatory system all round the body.

3) Today in the laboratory students ………..(carry out) an experiment.

4) The explanation ……………(be) not evident enough.

5) By weighing the leaves at the start and at the end of the experiment we ………..(obtain) quite accurate data, showing the result of evaporation.

6) It is a dry season now and wildebeests ………( migrate) in search of green grass.

7) Luminous bacteria ……… (live) in symbiosis with different marine animals.

8) The zoo …… (open) at 9 a.m.

9) The experiment ……… (start) at 12.00 tomorrow.

10) It is spring now. Birds …….. (sing) and ………(build) nests.

11) More and more species ……… (die out) because people …….. (destroy) their habitats.

Complete the sentences with the verb in the correct form: Present Simple or Present Continuous Tense.

1) With what man ( think)? He( think) with the brain?

2) Where hares ( live)? They ( live) in the woods.

3) Animals (not speak).

4) Fish ( breathe) with gills and ( swim) with fins.

5) Plants (not move) about. They ( have) no power of locomotion.

6) The horse ( be) a domestic animal.

7) The fox ( be) a domestic animal? No, it (not be).

8) The fox ( live) in water? No, it (not do).


Читайте также


  • - Complete the questions to the text and answer them.

    Exercises Complete the sentences with the verb in the correct form: Present Simple or Present Continuous Tense. WHAT DRAGONFLIES SEE - AND HOW 1) Dragonflies …( help) scientists to learn more about how animals and humans …(see). These insects are especially favorable for such studies because of their huge eyes with large cellular components. They …(study) the eyes of adults and nymph dragonflies for their sensitivity to light and their ability to discriminate different colors. ... [читать подробенее]