cough once
医生说：“是的，你再咳一下”
The doctor said, “Yes, cough once more.”
— 蓝白红三部曲之蓝 (1993)
咳一下!
Cough!
— 再见列宁 (2003)
他说…现在试试咳一下
He said… try coughing now.
用力咳一下!
Cough hard!