Learning english

6. ‘To cost an arm and a leg"- something is very expensive.
"Fuel these days costs and arm and a leg."

7. ‘A piece of cake"- something is very easy.
"The English test was a piece of cake."

8. ‘Let the cat out of the bag" - to accidentally reveal a secret.
"I let the cat out of the bag about their wedding plans."

9. ‘To feel under the weather" - to not feel well.
"I"m really feeling under the weather today; I have a terrible cold."

10. ‘To kill two birds with one stone" - to solve two problems at once.
"By taking my dad on holiday, I killed two birds with one stone. I got to go away but also spend time with him."