a tuft of beard的用法和样例：
- She sat down on a tuft of grass.
- He was just picking up the telephone, when the door opened and a squarish face with a tuft of beard on its chin peered round the door as if wondering whether to come in or wait outside.
- A tuft of hair, especially a forelock.
- We saw a rabbit on a tuft of grass.
- The bird has a tuft of red feathers on top of its head.
- The bird has a tuft of feathers on top of its head.