I used a knife to cut the vegetables.

She knifed him in the back.

He balanced on the knife-edge of success and failure.

He always carries a sheath knife with him when he goes sailing.

He used a bowie knife to hunt.

I need a fruit knife to cut the watermelon.

I used a carving knife to slice the roast beef.

I need a fish knife to cut the fish.

He always carries a clasp knife with him.

He pulled out a flick-knife and threatened the man.