As timid as a mouse.
Cannot say 800 to a goose.
Afraid of one's own shadow.
Have one's heart in a nutshell.
To be chicken-hearted.
As timid as a rabbit.
eg:She is as timid as a mouse and does not know how to answer the question.
同義詞:前怕狼,后怕虎 Too much taking heed is loss.
反義詞:一身是膽 With plenty of guts.