1. play a leading / minor / key role
play a role:
— play a part in a play; take part in and make changes happen
Examples:
play a leading / minor / key role
She plays the leading role in a television show.
Does religion have a role to play in society today?

2. The forest extends in all directions as far as the eye can see.
—(to cause ) to reach, stretch, continue; to add to in order to make bigger or longer
Examples:
The forest extends in all directions as far as the eye can see.
We have planned to extend our publishing of children’s books.
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3. I would like to extend my gratitude to you for your kindness.
—to offer or give
Examples:
I would like to extend my gratitude to you for your kindness.
The government is extending aid to people who have been affected by the earthquake.
The bank has agreed to extend us money to buy our house.

4. explore:
— to search and discover
Examples:
If I have time in the summer, I’d like to explore some of the less well-known areas of the country.
Let’s explore this issue / question / topic / idea more fully.
Psychotherapists explore people’s past in order to help them understand their present feelings and behavior.

5. interaction:
— communication or reaction (between)
Examples:
Language games are usually used to encourage students’ interaction.
There is not enough interaction between the management and the workers.

6. — the way to deal with something
approach: n.
— the way to deal with something
Examples:
Since our research so far has not produced any answers to this problem, we need to adopt a different approach to it.
Michael is always very logical in his approach.
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7. Many kinds of birds fly south at the approach of winter.
approach: n.
— coming near
Examples:
Many kinds of birds fly south at the approach of winter.
The hospital is making approaches to local businesses in their bid to raise money.
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8. — to deal with something
approach: v.
— to deal with something
Examples:
We needs to find the best way of approaching the problem.
I must tell him that I can’t loan my few savings to him, but I don’t know how to approach this topic.
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9. approach: v.
— to come near or nearer to (sth. or sb.) in space, time, quality, or amount
Examples:
We could just see the train approaching in the distance.
In my opinion, no other composers even begin to approach Mozart.
We’ve just approached the bank for/ about a loan.

10. conventional: adj.
—(of way of behaving) in the way which is accepted by most people in a particular society and often follows a way of thinking or a custom belonging to the past
Examples:
They’re such a conventional family---they must have been horrified when their son died his hair pink.
As an artist I find him very dull and conventional---he’s not prepared to try anything new.
Alternative medicine can sometimes provide a cure where conventional medicine cannot.
In some countries, it’s conventional for guests to wear black or dark-colored clothes.

11. accessible: adj.
—easy to reach, get into, obtain, use, or talk to
Examples:
The resort is easily accessible by road, rail, and air.
Storing customer details on computer makes them readily accessible.
The problem with some of these drugs is that they are very accessible.
I think you will find she’s very accessible.
The students’ union succeeded in making the computer lab accessible to all the students.

12. — a subject or problem which people are thinking and talking about
issue: n.
— a subject or problem which people are thinking and talking about
Examples:
environmental / scientific / personal / family / ethical issue
The group had prepared a report on the issues of management and staff training.
The need for more staff is not on issue (= there is no disagreement about it), but finding suitable people has not been an easy job.
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13. issue: n.
— a subject or problem which people are thinking and talking about
Examples:
The burning issue (= what we are discussing at present) is whether we should buy a new car.
Don’t worry about who will do it. That’s just a side issue (= not the main problem).

14. — the place sth. comes from or starts at, or the cause of sth.
source: n.
— the place sth. comes from or starts at, or the cause of sth.
Examples:
Oranges are a good source of vitamin C.
The reporter refused to disclose her sources of information.
Experts are trying to find /locate /track the source of the pollution in the water supply.
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15. source: n.
— the place sth. comes from or starts at, or the cause of sth.
Examples:
We must find a good source of income. Children are growing up quickly and we need money for their education.
Clara was a source of inspiration for Schumann.
The rumor must be stopped at the source.

16. available: adj.
— able to be obtained, used or reached
Examples:
Is this dress available in a larger size?
I’m afraid that I’m not available to do the show on the 19th.

17. exchange: v.
— change (sth.) for sth. else
Examples:
My uncle bought me this shirt as a birthday present but I don’t like the color, so is it possible to exchange it for a different one.
They exchanged heated words, and finally came to a blow.
Where can I exchange dollars for pounds?

18. in addition (to):
— besides; furthermore; used when adding another fact to what has already mentioned
Examples:
The hotel itself can accommodate 80 guests, and in addition, there are several self-catering apartments.
He’s now running his research company. That’s in addition to his job in the university.
In addition to the apples you asked for, I bought you some oranges.

19. project: n.
— a piece of planned work or activity which is completed over a period of time and intended to achieve a particular aim
Examples:
He was employed by the company to work on the Jinyuan housing project.
In our third year at college everyone had to do a special project.

20. register: v.
— to put information into an official record
Examples:
She bought a new car and registered it in her name.
If you don’t have a job, to claim money from the government, you must first register (as unemployed) at the job center.
How many students have registered for the online course?