The word "KE" is a conjunction. KE=THAT Example: Khane'i KE abi ast. Translation: A house THAT is blue. Example: Mashini KE saree' harekat mikonad. Translation: A car THAT moves fast. Sometimes "KE" means "SO" and since you are a beginner in learning Farsi, I don't recommend you to learn it. Example: KE mikhahi be khaneye Ali beravi? Translation: SO you want to go to Ali's place? Example: KE mikhahi pool-haye man ra kharj koni? Translation: SO you want to spend my money? NOTE: Whenever the word "KE" means "SO", it comes at the beginning of the sentence. NOTE: Whenever in your sentence "KE" means "SO", your sentence is for threatening!

There is another KE which means WHO in Farsi. Example: mikhahi ba ke sohbat koni? Translation: Who do you want to talk to?

که=that the usage of ke is like that as a conjunction in english