envelope test

例句：

1. 1.The envelope test is a common method for testing the integrity of envelopes.
   信封测试是一种常用的检验信封完整性的方法。
2. 2.During the envelope test, the contents are placed inside the envelope and sealed.
   在信封测试过程中，将内容物放入信封并密封。
3. 3.The envelope test was used to ensure that the package arrived intact.
   信封测试被用来确保包裹完好无损地到达。