说明 “to prove”
The verb 说明 
is used in compound sentences.
In the first part of a sentence we state a reason or an argument for something, and in the second part of a sentence we state what it means.
is used in compound sentences.
In the first part of a sentence we state a reason or an argument for something, and in the second part of a sentence we state what it means. Pay attention
说明 is usually preceded by the demonstrative pronoun 这 .
.Examples
一万米都能坚持跑下来，这说明他身体很好
He can run 10,000 meters. It shows that he is in good health
yí wàn mǐ dōu néng jiānchí pǎoxiàlai, zhè shuōmíng tā shēntǐ hěn hǎo
他把这样的事情都告诉了你，说明他很信任你
If he told you everything, it means he trusts you
tā bǎ zhèyàng de shìqing dōu gàosu le nǐ, shuōmíng tā hěn xìnrèn nǐ
他昨天的作业都错了，说明他上课时没听懂
He did his homework wrong yesterday, which shows that he didn't listen to the teacher during the lesson
tā zuótiān de zuòyè dōu cuò le, shuōmíng tā shàngkè shí méi tīngdǒng
The verb 说明 also has the meaning "to explain".
Examples
你能说明一下电子邮件系统的工作原理吗？
Can you explain how the email system works?
nǐ néng shuōmíng yíxià diànzǐ yóujiàn xìtǒng de gōngzuò yuánlǐ ma
他们根本没说明这项工作该怎样做
They didn't even explain how to do the work
tāmen gēnběn méi shuōmíng zhè xiàng gōngzuò gāi zěnyàng zuò