8. Sequence of Tenses

Ex. 1. Rewrite these sentences following the rules of the sequence of tenses:

Model: He said, "The laws of physics are expressed in the terms of physical quantities". – He said that the laws of physics were expressed in the terms of physical quantities.

1. There are fundamental and derived quantities in physics. 2. Length and time are examples of fundamental quantities. 3. An ideal standard has two. principal characteristics. 4. He gave a lot of examples in his lectures. 5. They make convincing experiments. 6. She does not know how to take temperature. 7. The diagram was very good. 8. Then you choose your standard of length. 9. Some distances were measured in a direct way. 10. The signal travelled in a straight line. 11. The observers are moving in opposite directions. 12. One of the observers is sitting in the train. 13. Another observer is making the measurements. 14. Yard is used in English-speaking countries. 15. They will experiment on different objects. 16. His articles will be published in a lot of journals. 17. There are significant facts in his article. 18. The formula is quite correct.

9. Direct and Indirect Speech

Ex. 1. Write down the following sentences in indirect speech:

Model: He says: “They will experiment on different objects”. – He said that they would experiment on different objects.

1. Mike says: “They have dropped two objects from the top of the Mast”. 2. The teacher says: “They have brought a stone from the moon”. 3. Mary says: “Pete suggested a new idea but we did not accept it”. 4. Our teacher says: “The question was unanswered”. 5. The students of our group say: “We called it a “thought experiment”. 6. Bob says: “I have read his article several times”. 7. We say: “We haven't solved the problem yet”. 8. We ask: “Did they experiment on new materials?” 9. We ask: “What did you say about their work?” 10. Ted says: “He is holding something in his hand”. 11. Our teacher asks: “In what theory do the laws of motion and of gravitational force come together?” 12. Our teacher says: “A falling apple played its essential role in history of physics”. 13. Paul says: “They agreed with each other on a lot of points”. 14. He says “Write this word correctly”. 15. I say: “Do not go to the lab!”

Ex. 2. Render this dialogue in reported speech:

- When work is done what happens to the energy?

- Let’s consider a car. First, where is any petrol poured into?

- It’s poured into the tank.

- That’s right. This contains chemical energy. And what contains electrical energy?

- The car battery. Some of the electrical energy is used to overcome friction and to turn the engine.

- You are right. The energy used against friction is liberated as heat. What happens to the remainder energy?

- It becomes the energy of motion. The heat energy thus becomes mechanical energy and the car is made to move.

- Thus energy may exist in many forms.

10. Gerund

Ex. 1. Determine the functions of gerund. Translate the sentences:

1. Permitting electrons to pass freely through a substance is to conduct electricity. 2. There was much discussing of the new approach to the problem. 3. Understanding of the nature of the phenomenon is very important. 4. They began charging the substance immediately. 5. I was surprised at his operating the device so easily. 6. Du Fay electrified a glass rod by rubbing it with silk. 7. When a piece of amber is rubbed with cloth it acquires the power of attracting other things towards it. 8. Several methods of pushing extra electrons into matter have been devised since the days when electric charges were developed by rubbing amber with fur. 9. During the latter half of the nineteenth century many scientists studied the effects of passing electricity through gases. 10. The way of avoiding these difficulties is unknown at present. 11. It's useless devoting too much time to this problem without specifying all the details of the procedure. 12. The idea of using this technique is new and somewhat unexpected. 13. The model is tested by measuring these probabilities and coupling constants in various experiments. 14. The scientists found four events that could not in any way be explained without involving the presence of an unidentified particle with a new quantum number.

Ex. 2. Translate the following sentences. Is the “ - ing” form a participle or a gerund?

1. Swimming is my favourite sport. 2. Swimming in cold water he caught cold. 3. Testing will begin in a few minutes. 4. Testing these devices we sometimes find defects in them. 5. Reading stories about adventures excited the boy's imagination. 6. Reading stories about adventures he remembered his childhood. 5. Increasing the pressure we increase the force of friction. 6. Ice melting begins at 0°C. 7. Heating makes the molecules move faster.