standard air density

例句：

1. 1. The standard for measuring the length of a ruler is 20 cm.
   测量尺子长度的标准是20厘米。
2. 2.The company has set strict standards for its employees to follow.
   该公司为员工设定了严格的标准来遵守。
3. 3. The new policy aims to standardize the industry's practices across the board.
   新政策旨在全面标准化该行业的实践。