They may sound the same, but their spelling dictates their meaning:
1. Complimentary and Complementary: Complimentary with an “i” means to praise something or someone or to receive something for free; Complementary with an “e” means to complete something, usually achieving a type of balance.
a) The students received a complimentary drink with their meal.
b) The tour guide was very complimentary about the students’ behaviour during the long service.
c) The dark green shades of her scarf complemented Sybil’s hazel eyes.
2. Affect and Effect: Affect means to influence; Effect as a noun refers to a result and as a verb means to accomplish something.
a) Lack of exercise affects a person’s overall health.
b) The special effects used in The Life of Pi made it seem like the tiger was real.
c) Will Students Council be able to effect a positive change by allowing more grade nine students to be members?
3. Lose and loose: Lose means to misplace or not to win, while Loose means not tight or in its verb form, to release
a) Did you lose your keys?
b) If the team loses this game they won’t advance to the finals.
c) She tied the bandanna loosely around her dog’s neck so it would be comfortable.
d) At the sound of the horn, the hunting dogs were loosed on the green.