only when
艾蜜莉六岁像一般小女孩喜欢爸爸抱抱但爸爸只在…每月身体检查时才抱她
At six years old, Emily is like any other little girl who loves being hugged by her dad, but he only hugs her during her monthly physical checkups.
— 天使爱美丽 (2001)
不，需要时才用
No, only use it when needed.
— 邮差 (1994)