Sure, let's complete each group of sentences with one of the verbs provided. Each verb will be used once only.

1. You can't **let down** all the people who are relying on you.
Someone has **run down** my tyres!
I had to **lay down** the dress because it was too short.

2. He might **fall down** if he climbs that tree.
The argument seems to **break down** in several places.
The houses will **fall down** eventually if they aren't repaired.

3. Don't let these problems **get down** (you) so much!
Did your secretary **get down** everything that was said?
Please **get down** out of that tree immediately!

4. We had to **break down** the door to get in.
Many people **break down** because of the pressure of their work.
Did the car **break down** on the motorway?

5. Could you **wind down** the window and let some air into the car?
I find it hard to **wind down** after work?
We had to **wind down** the business and sack some of the staff.

6. Why don't they **lay down** their guns and stop the fighting!
The regulations **lay down** minimum safety standards.
It's the young who mostly **lay down** their lives for their country.

7. You must **keep down**! Someone might see you!
The boss wants to **keep down** costs as much as possible.
He used a wave of terror to **keep down** the entire population.

8. She was **run down** by a car while crossing the road.
Services are being **run down** to save money.
If the batteries **run down** the radio won't work so well.

Explanation of meanings:
1. **Let down**: To disappoint someone.
**Run down**: To damage or reduce the quality of something.
**Lay down**: To put something down or to establish rules.

2. **Fall down**: To collapse or drop to the ground.
**Break down**: To stop functioning or to fail.

3. **Get down**: To make someone feel sad or to write something down.

4. **Break down**: To force entry or to collapse emotionally or physically.

5. **Wind down**: To relax or to reduce operations.

6. **Lay down**: To put something down or to establish rules.

7. **Keep down**: To stay hidden or to control or reduce something.

8. **Run down**: To hit someone with a vehicle or to reduce in power or quality.