Rule of 7 in research. You can find out anything if you are willing to go seven levels. If the first source you ask doesn’t know， ask them who you should ask next， and so on down the line. If you are willing to go to the 7th source， you’ll almost always get your answer.

水产养殖的未来在于可持续发展和环境保护。

机械感觉系统是大自然的工程杰作。

The best performances come from the heart, not just the voice.