1, first control. Scientific experiments require that according to the needs of research, with the help of various methods and technologies, the interference of various irrelevant factors that may affect science can be reduced or eliminated, so that the research object can be understood in a simplified and purified state. Third, causality. Experiment is an effective tool and necessary way to discover and confirm the causal relationship between things.

2. Method 3: google and other translation tools use google to translate words in other people's papers into English, and then translate them back, the sentence structure will change, and then you can successfully avoid duplication by modifying the language diseases yourself. Advantages: convenient and quick, and can be modified in large sections.

3. The top two lines; The title is "TimesNewRoman" in font No.5, which is bold and placed in bold square brackets. Top grid placement; There is a space between the back content and the bold square brackets in front, without any other punctuation marks; No.5 "TimesNewRoman" font is adopted, which is not bold; Single spacing.