填空题

  • A. Langmir and Schaefer’s work for the GE Company
  • B. Langmir and Schaefer’s discovery of rain-forming
  • C. Men’s knowledge of rain-formingE. Schaefer’s discovery by accident
  • D. Schaefer’s several unsuccessful experimentsF. Langmir and Schaefer’s successful cooperation

Paragraph 2 ______

【参考答案】

C