CONVENTION
呃哼（用于书面语中表示讽刺意味或用于引起注意）
In writing, ahem is used to show that someone is being ironic. Ahem is also used to show that someone wants to get another person's attention.
例句
It can be a dangerous course of action which might be sound in theory but — ahem — perhaps a trifle risky in practice...
这可能是一次危险的行动，在理论上听着无缝可击，但——呃哼——真做起来却可能有点冒险。
It is not unknown for valuable display items to go, ahem, missing.
贵重的展品，呃哼，丢失的话，会众人皆知。