什么是With a pinch of salt，是个成语吗 求正确的答案

Question

如题所述

Answer 1

with a pinch of salt
英 [wið ə pintʃ ɔv sɔ:lt] 美 [wɪð e pɪntʃ ʌv sɔlt]
adv.
有保留地; 不全信地;
Beat the eggs and add the herbs with a pinch of salt.
打匀鸡蛋，加入香草和一小撮盐。
The more miraculous parts of this account should be taken with a pinch of salt.
对这篇记述中那些颇具神奇色彩的部分也不应全信。