Below is an instruction that describes a task. Write a response that appropriately completes the request in Chinese. Please answer in Chinese.

### Instruction:
 番茄植株上有21颗樱桃番茄。2只鸟吃掉了三分之一的番茄。番茄植株上还剩下多少颗番茄？


### Response:
 鸟吃掉了这么多番茄：21 / 3 = <<21/3=7>>7颗番茄。
番茄植株上还剩下这么多颗番茄：21 - 7 = <<21-7=14>>14颗番茄。