These words all mean to know or realize sth, for example why sth happens, how sth works or what sth means. 以上各词均含懂得、理解、认识到之义。

• understand to know or realize the meaning of words, a language, what sb says, etc; to know or realize how or why sth happens, how it works or why it is important 指懂、理解、领会（词义、语言、话语等），了解、认识到、明白（事情如何或为何发生、如何起作用或为何重要等）：◆I don't understand the instructions. 我不懂这些指令的意思。◆Doctors still don't understand much about the disease. 医生对这种疾病还了解不多。
• see to understand what is happening, what sb is saying, how sth works or how important sth is 指理解、明白、领会（正在发生的事、某人的话、某事如何起作用或重要性如何）：◆'It opens like this.' 'Oh, I see.' “这样就打开了。” “哦，我明白了。”◆Oh yes, I see what you mean. 噢，我明白你的意思了。
• get (informal) to understand a joke, what sb is trying to tell you, or a situation that they are trying to describe 指理解、明白（笑话、某人试图告知的事或描述的情况）：◆She didn't get the joke. 她听不懂那个笑话。◆I don't get you. 我搞不懂你的意思。
• follow to understand an explanation, a story or the meaning of sth 指理解、明白（说明、故事、意思）：◆Sorry—I don't quite follow. 对不起，我不太懂你的话。◆The plot is almost impossible to follow. 故事情节几乎叫人不明所以。
• grasp to come to understand a fact, an idea or how to do sth 指理解、领会、领悟、明白（事实、想法或如何做某事）：◆They failed to grasp the importance of his words. 他们没有理解他的话的重要性。

understand or grasp? 用 understand 还是 grasp？

You can use understand or grasp for the action of realizing the meaning or importance of sth for the first time. 第一次意识到某事的意义或重要性可用 understand 或 grasp：◆It's a difficult concept for children to understand/grasp. 对孩子来说，这是一个很难理解的概念。 Only understand can be used to talk about languages, words or writing. 只有 understand 可用于理解语言、词汇或文章等：◆I don't grasp French/the instructions.

• comprehend (often used in negative statements) (formal) to understand a fact, idea or reason （常用于否定句中）指理解、领悟、明白（事实、想法或原因）：◆The concept of infinity is almost impossible for the human mind to comprehend. 无穷的概念几乎是人类的大脑无法理解的。

Patterns

• to understand/see/get/follow/grasp/comprehend what/why/how…
• to understand/see/grasp/comprehend that…
• to understand/see/get/grasp the point/idea (of sth)
• to be easy/difficult/hard to understand/see/follow/grasp/comprehend
• to fully understand/see/grasp/comprehend sth