Idioms
by Clarisa Gonzalez

1. In hot water
2. hit the sack
3. Hold your horses
4. a piece of cake
5. Relative clauses
5.1. They don't know where the keys are. (They don't know the place that the keys are.)
5.2. He eats what he likes. (He eats the things that he likes.)
5.3. That is why they are happy(That is the reason that they're happy.)
6. Relative pronuns
6.1. Who
6.1.1. The woman who works at my office is very efficient
6.2. Which
6.2.1. That is the airplane which had a problem during takeoff.
6.3. Whose
6.3.1. This is the dog whose owner I met yesterday.
6.4. What
6.4.1. Tell me what you want to know
6.5. That
6.5.1. The woman that works at my office is very efficient.