on the tip of one's tongue 就在嘴边

【讲解】

tip的意思是“顶端”，从字面看，该习语的意思是“就在舌头尖儿上”，实际是“差一点就想起，就在嘴边。”

【对话】

A:Interesting lectures, aren't they?
A:演讲很有意思，是吧？
B:Yes, very. I thought the last speaker was especially good.
B:是的，非常有意思。我觉得最后一个演讲者尤为出色。
A:Do you know his name?
A:你知道他的名字吗？
B:Let me see. It's an unusual name. It's on the tip of my tongue but I just can't get it out.
B:让我想想，是个挺特别的名字，就在嘴边，可说不出来。