The first two words are already set for you to do. All you need to do is continue the sentence by joining the two sentence together with the comma
( , ) since the first sentence is a conditional phrase.
1. If he is not here, I must start the meeting without him in five minutes.
2. If you can't attend the course, you buy the CD-ROMs.
3. As soon as I have a swim, I finish this work.
4. If no one speaks the language, it dies.
5. Unless you start studying, you fail the exam.
