1.

Anna's fed up with the company and she's intending to leave work as soon as she can.

no

Anna's fed up with the company and she's got longer than she has to.

2.

Susan picked the baby up gently, because she didn't want to wake him.

to

Susan picked the baby up gently so him.

3.

They were able to creep away unobserved because it was very dark.

owing

They were able to creep away unobserved it was very dark.

4.

The car was redesigned and, as a result, sales rose rapidly.

resulted

The successful redesigning of the car in sales.

5.

Despite improving his performance. Smith is still not in the top three for the 10.000 metres.

led

The improvement in Smith's performance in the top three for the 10,000 metres.

6.

We should leave about six, otherwise we might not get there in time for dinner.

set

If six, we might not get there in time for dinner.

7.

You should make the sauce thicker if you want to improve the flavour.

thicken

You'll order to improve the flavour.

8.

After several years, heavy traffic caused the bridge to collapse.

due

The collapse several years of heavy traffic.