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

### Instruction:
 里斯每周练习钢琴四个小时。五个月后，他将练习多少小时？


### Response:
 五个月有5 x 4 = <<5*4=20>>20周。
如果里斯每周练习四个小时，五个月后他将练习20 x 4 = <<20*4=80>>80个小时。