Sure! Here are the completed sentences:

### I. Complete these sentences with although or in spite of / despite

1. **Although** she is an accountant, she never seems to have any money.
2. **In spite of** being an accountant, she never seems to have any money.
3. Mark went on working **although** he felt unwell.
4. Mark went on working **in spite of** feeling unwell.
5. They slept soundly **although** the night air was hot.
6. They slept soundly **despite** the hot night air.
7. She was absent from her class **because** she was ill.
8. She was absent from her class **because of** her illness.

### II. Complete these sentences with because or because of

1. **Because of** the rough sea, the ferry couldn't sail.
2. **Because of** the traffic jam, I came late for the interview.
3. **Because** the meeting is at 2:00, I won’t be able to see you.
4. I can't print out the letter **because** my computer is not working.
5. We couldn't get to his house **because of** flooding on the road.
6. She couldn’t complete the work **because of** her illness.