locked middlings

例句：

1. 1. Thelocked up middle is the part of a molecule that remains unaffected by changes in temperature and pressure.
   锁住的中间物是分子中不受温度和压力变化影响的部分。
2. 2. The locked up matter is the substance that remains unchanged even after it has been heated or cooled.
   锁住的中间物是物质，即使加热或冷却后仍保持不变。
3. 3. The locked up material is the substance that cannot be easily broken down into smaller molecules.
   锁住的中间物是物质，不能轻易地分解成更小的分子。