a grain of

基本解释

A little red hen once found a grain of wheat.
一次，一只红色的小母鸡找到了一粒小麦。
Tiny glass tubes, about half the width of a grain of rice, are carefully placed in the deep brain of an anaesthetized mouse.
很多极微小的玻璃管，大概是一粒米宽度的一半，被小心翼翼的置入一个被麻醉小鼠的大脑深部。
On my last holiday in the Bahamas, as I walked along the beach feeling the gentle waves wash over my feet, I felt part of the universe, even if only a minuscule one, like a grain of sand on the beach.
在巴哈马最后一次度假的时候，当我沿着海滩散步的时候，温柔的海水拂过我的脚时，我感觉到我与宇宙融为了一体。尽管只是如海滩上的一粒沙子那样渺小的一部分。

Researchers compared the use of fertilizer in three areas that grow maize as a major grain: China,Kenya and the United States.
in some ways, one has to admit also there maybe a grain, if not more than a grain of truth in what he seems to be saying.
我们多么不喜欢他，但必需承认,他可能有点儿道理，但就那么点儿,关于他所说的话。
耶鲁公开课 - 政治哲学导论课程节选
Alright. So take it with a grain of salt.
好，我们就说到这里。
哈佛公开课 - 计算机科学课程节选

In fact, take all such daily explanations of market turbulence with a grain of salt.
FORBES: Market Turbulence Or Deeper Ills?