bite : 指用牙齿钳住或切断，或咬一口。
- He bit into the apple.
- He bites his fingernails.
chew : 指用牙磨碎，或者为品尝味道而嚼。
- This meat is difficult to chew.
- You don't chew your food enough - that's why you get indigestion.
- Would you like some gum to chew?
- She gave the children some sweets to chew (on) during the long car journey.
- She sat in the dentist's waiting room, nervously chewing (at) (= biting) her nails.
gnaw : 指连续不断用齿咬。
- Babies like to gnaw hard objects when they're teething.
- A dog lay under the table, gnawing on a bone.
snap : 指突然猛咬。
- The guard dog was snarling and snapping behind the fence.
- The dogs snarled and snapped at our heels.