1.To have a sweet tooth

              Children usually have a sweet tooth.they love it.

2.To have something on the tip of ones tongue

             Its on the tip of my tongue but I cant remember

3.To turn a blind eye to something

           I prefer turning a blind eye to my debts.

4.Put your foot down

            She was out of control but her parents finally decided to put their foot down.

5.Play it by ear

            We don’t have a plan. We’ll just have to play it by ear.

6.At each other's throats

            The two boys were at each other's throats when they entered the room.

7.Sweat it out

            We had to sweat it out with no food while our car was being repaired.

8.Skin-deep

            I believe that the speaker's interest in the environment is only skin-deep.

9.A shoulder to cry on

               I gave my friend a shoulder to cry on when I met him at the coffee shop.

10.A pain in the neck

              Our customer is a pain in the neck and is always complaining about something.

11.Breathe easy

               I could breathe easy after I finished my essay and gave it to my teacher.

12.As dry as a bone

              The river bed was as dry as a bone at the end of the summer.

13.In cold blood

             The man was murdered in cold blood by a group of criminals.

14.Blow your mind

             The film was amazing. Go and watch it. The 3D effects will really blow your mind.

15.Old hand

               You’re an old hand at your job.

16.Back to the wall

              If you have your back to the wall, you are in serious difficulty

17.To wash one's hands of

               I wash my hands of this whole affair

18.Under one’s thumb

             She has her husband under her thumb. He would do anything for her

19.Armed to the teeth

              The terrorist were armed to the teeth.

20.Drag your feet

             You have a lot of work do today, so stop dragging your feet and finish this task.