Present perfect finished or unfinished time present perfect tense

PRESENT PERFECT - FINISHED OR UNFINISHED TIME

Faith Evans began singing in a church when she was four years old. At the age of 25, she became a popular singer and song writer. Faith Evans has been very busy this year. She has written and produced songs for other singers. She has recorded with Ray Charles and Whitney Houston. And she has just made a new album of her own, “Keep the Faith”. Faith Evans wrote most of the songs on the album. She said they were about experiences in her life.

# Underline the examples in the text of the Past Simple, then write the base forms

# All the other verb forms in the text are examples of the Present Perfect.

Complete this rule.

The Present Perfect is formed with the auxiliary verb ………… + the …… ……

* Why are different tenses used?

+ She began singing when she was 4 years old.

+ She has been very busy this year.

+ She became a popular singer at the age of 25.

+ She has recorded with other singers.

Notice that we normally use the Past Simple with time expressions which refer to a

finished time , like yesterday, last week, three years ago, when …

1. Grammar

1.1/ Finished or unfinished time. Put the expressions in two lists:

a long time ago in 1990 at 8.30

when I was nine in my life the day before yesterday

last year today this year

1.2/ Choose the correct tense:

a. The Earth ( served / has served ) us well.

b. Scientists ( made / have made ) a lot of discoveries.

c. The scientists of the eighteenth century ( discovered / have discovered) a lot of things about air and water.

d. Men ( wanted / have always wanted ) to fly like birds.

e. ( Have you ever climbed / Did you climb ) a mountain in your life?

f. In 1665, at the age of 23, Newton ( has developed / developed ) his famous laws of motion.

g. Fifty years ago people ( thought / have thought ) that sending a rocket to the moon was impossible.

1.3/ The Present Perfect is also used with since and for. Notice the difference between since and for

since + a particular time

for + a duration of time

Example :

+ I’ve been here since 7 o’clock.

+ I’ve known him for many years.

Put since / for into each gap

a. I haven’t seen Tom…………………Monday.

b. I haven’t seen Tom …………………three months.

c. …………………Christmas, the weather has been quite mild.

d. That’s a very old car. I’ve had it ………………ages.

e. My sister has been a student ……………… last year.

f. Robert has studied weather and storms …………………he was at school.

1.4/ To practice irregular past participles, begin your response with “ I have

never….”

Example: see that movie

I have never seen that movie.

a. drive a truck b. ride a horse

c. buy an airplane d. win a lottery

e. make a generator f. fly in a balloon

g. understand Einstein’s theory of relativity
2. Speaking and listening

Work in pairs

Ask and answer questions beginning How long ………?

about where you and your partner live, work, study and about some of your

professions. Then try to get some more information.

How long have you lived in……………………?

How long have you worked.……………………?

What did you do before that?

How long have you had your bicycle?

Where did you buy it?

3. Revision exercise

You’ve read an advertisement for a second–hand car. You want to get some

information about the car. Think of questions to ask the owner:

For sale 1989 Ford Cortina. Red. 1 owner. No accidents 20,000 miles. VND 120,000,000.

Example :

How many owners has it had?

• Reading and speaking

1. You are going to read a text about forces. A force can be generally defined as any

push or pull. Give some examples of forces of nature you know.

2. Form adjectives from the following nouns:

Example:

electromagnet ( n ) → …………………

friction ( n ) → …………………

3. Read quickly the whole text. Fill in the summary chart.

We have used F as a generic symbol for force. We have also used other symbols: W for the weight of a body, I for the pull from a cord under tension, f for a frictional force, N for a normal force, and D for the drag force exerted, for example, by air on a sky diver. At the fundamental level, all these forces fall into two types:

(1) the gravitational force, of which weight is our only example, and ( 2 ) the electromagnetic force, which includes – without exception _ all the others. The force that makes an electrically charged balloon stick to a wall and the force, with which a magnet picks up an iron nail are other examples of the electromagnetic force. In fact aside from the gravitational force, all forces that we can experience directly as a push or pull are electromagnetic when examined closely. That is, all such forces, including frictional forces, normal forces, contact forces, drag forces, and tension forces, involve, fundamentally, electromagnetic forces exerted by one atom on another. The tension in a taut rope, for example, is maintained only because the atoms of the rope attract one another.

The only other fundamental forces known to occur both act over such short distances that we cannot experience them directly through our sensory perceptions. They are the weak force, which is involved in certain kinds of radioactive decay, and the strong force, which binds together the constituents of protons and neutrons and which is the “glue” that holds together an atomic nucleus.

Physicists have long believed that nature has an underlying simplicity and that the number of fundamental forces can be reduced. Einstein spent most of his working life trying to interpret these forces as different aspects of a single superforce. He failed, but in the 1960 s and 1970 s, other physicists showed that the weak force and the electromagnetic are different aspects of a single electroweak force. The quest for further reduction continues today, at the very forefront of physics.

The forces and the particles of nature are intimately connected with the origin and development of the universe. With a force unification theory in hand, it might be possible to answer questions such as: “ How did the universe evolve to its present state?” and “What will the universe be like in the future?”

4.1/ Answer the following questions:

a. What generic symbol have we used for force?

b. What types of forces at the fundamental level do we have?

c. What is the force with which a magnet picks up an iron nail?

d. Why is the tension in a taut rope maintained?

e. What is a weak force? What is a strong force?

4.2/ Are the sentences true or false. Correct the false sentences:

a. Physicists have long thought that nature is a complicated system.

b. Einstein believed in the existence of a single superforce.

c. Physicists have tried to reduce the number of fundamental forces so far.

d. Electroweak force includes the weak force and the strong force.

e. A force unification theory may help physicists study the future universe.

5. Think further and complete the sentence below:

5.1 “ The earth can be thought of as being surrounded by a gravitational field that

interacts with objects and causes them to experience………….……”

5.2 Discuss in groups:

a. Which of the four above–mentioned forces makes paint cling to a wall?

b. Do you think frictional forces are often advantageous or necessary?

Give examples.

# Present Perfect

* The Present Perfect expresses actions that happened before now at an unspecified time in the past. (The exact time it happened is not important)

* The Present Perfect is also used with since and for to express a situation that began in the past and continues to the present.

1. The astronomers from San Francisco State University have just found three large planets around Upsilon Andromedae.

2. Seoul – South Korea has ended a year–long recession.

3. Many automobile passengers have suffered neck injuries when struck by cars

from behind.
• Translate into English:

Оптиката е клон на физиката, който включва поведението и свойствата на светлината, включително и нейното взаимодействие с материята, както и изграждането на инструменти, които я използват или откриват. Оптиката обикновено описва поведението на видимата, ултравиолетовата и инфрачервената светлина. Тъй като светлината е електромагнитна вълна, други форми на електромагнитната радиация, като рентгеновите лъчи, микровълните и радиовълните, показват сходни свойства.

Optics is the branch of physics, which involves the behavior and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behavior of visible, ultraviolet, and infrared light. Because light is an electromagnetic wave, other forms of electromagnetic radiation such as X-rays, microwaves, and radio waves exhibit similar properties.
TANSLATION FOR HOMEWORK

Definition



Basic forces in nature are the forces governing macroscopic as well as microscopic world. These are gravitation forces, weak forces, electromagnetic forces and nuclear forces.
Introduction

In daily life, we come across many kinds of forces like friction forces, electrostatic forces, magnetic forces, viscous forces etc. These forces are observed to be acting between macroscopic objects. For instance, while walking on rough horizontal surface, the frictional forces are acting between our feet and rough surface. All the forces that we feel in macroscopic world are categorized basically into two groups

• 
  Gravitational forces
  
• 
  Electromagnetic forces
  

• 
  The weak (nuclear) forces
  
• 
  The (strong) nuclear forces
  

These are:

1. 
   Gravitational Forces
   
2. 
   Electromagnetic forces
   
3. 
   Weak forces
   
4. 
   Nuclear forces