[00:00.00]a pen     pens
[00:03.81]a map     maps
[00:08.52]a pet     pets
[00:13.45]a spade     spades
[00:18.52]a letter  letters
[00:22.33]a
[00:25.43]一个
[00:28.53]pen
[00:29.36]钢笔
[00:30.20]map
[00:31.23]地图
[00:32.26]pet
[00:33.61]宠物
[00:34.95]spade
[00:36.41]锹
[00:37.88]letter
[00:39.03]信