1. My boss tries really hard to help me.
effort
My boss really to help me.

2. It's a lot easier to sell a car when it's in perfect conditions.
much
You can sell a car when it's in perfect conditions.

3. Sheila was too tired to read the book.
that
Sheila was she could not read the book.

4. You must wear a helmet when riding a motorbike.
all
Helmets must be worn when riding a motorbike.

5. He was told to wait there by the secretary.
who
It was the secretary to wait there.

6. London is more modern than Liverpool.
as
Liverpool is London.

7. She took an umbrella but it was not necessary.
taken
She an umbrella.

8. As the company representative I'd like to welcome you.
behalf
I'd like to welcome you the company.

9. You should buy a new computer.
were
If , I would buy a new computer.

10. The police found out he wasn't responsible for the accident.
fault
The accident was .