1. Choose the content of the text message that you can understand and understand it! Is this expression correct? 2. Choose the content of the text message that you can understand and understand it.

"Understand" is a verb, and "come" and "go" are both adverbials.

One of the characteristics of Chinese grammar is omission. Words that do not affect the general meaning are often omitted.

The reason why both "come" and "go" can be used: Just like the Cantonese people in China say "I go first" when expressing "I go first", they all express the same meaning. The speaking habits of a place are different, and the modification of words and methods will also be somewhat different. "Lai" and "Go" have completely opposite meanings when taken alone, but when put in this sentence, "Lai" and "Go" bring out the expressive diversity of Chinese words and do not affect the meaning. expression.

If there is no specific environment to limit the content of expression, I personally think all three are correct.