@learnativenglish: Do you see the pattern? The in- prefix becomes im- for adjectives that start with p and m Im- makes the word negative Ex. Impossible = Not Possible Possible → Impossible Polite → Impolite Measurable → Immeasurable Movable → Immovable Patient → Impatient Permeable → Impermeable Perfect → Imperfect Probable → Improbable #english #learnenglish #prefix