1 - You must never take your helmet off while you are riding a motorcycle.

all
Helmets must be worn -- at all times when riding a motorcycle.

2 - They wanted to apologize for their behaviour: that's why they paid for dinner.

order

They paid for dinner -- in order to apologize for their behaviour.

3 - It isn't necessary to bring skis as they are included in the package.

have

You -- don't have to bring skis as they are included in the package.

4 - I thought parking was allowed here.

under the impression

I -- was under the impression that parking was allowed here.

5 - Simon said, "I will be playing tennis when you arrive."

he

Simon said -- he would be playing tennis when I arrived.

6 - When I was a child, we would go to the local park every Saturday afternoon.

used

When I was a child, -- we used to go the park every Saturday.

7 - His daughter continued to cry until he could not be seen any longer.

sight

She continued to cry until he -- was out of sight.

8 - I'm afraid that car is just too expensive.

means

That car is -- beyond my means.

9 - They moved to this village in 1999.

They -- have lived in this village since 1999.

10 - One other thing before I forget - Don is coming to visit next weekend.

by

-- By the way, Don is coming to visit next weekend.