一、选择括号中适当的词填空。
1. You may watch cartoons (if/ unless) you finish your homework.
2. Le Yue won't cook such good pizza (if/ unless) her mother helps her.
3. Wang Fan didn't catch the early bus (because/ so) he got up late this morning.
4. (Since/ So) all the viewers are here, let's start our project now.
5. They have left the small village (because/ so) they finished the task.

1. if 2. unless 3. because 4. Since 5. because