拳头

例句：

1. 1. She uses her thumb to openthe door.
   她用拇指开门。
2. 2. The doctorexamined his thumb and found it swollen.
   医生检查了他的拇指，发现它肿胀了。
3. 3. He put his thumb onthe table to steady himself.
   他把拇指放在桌子上稳住自己。