1sieve 
/ˈsɪv/ noun
plural sieves /ˈsɪv/ noun [count] : a kitchen tool that has many small holes and that is used to separate smaller particles from larger ones or solids from liquids
have a memory/mind like a sieve
informal : to have a very bad memory : to be unable to remember things
▪ I'm sorry. I have a memory like a sieve. What was your name again?
▪ I'm sorry. I have a memory like a sieve. What was your name again?
