methaldehyde

例句：

1. 1. The laboratory used formaldehyde to preserve the samples.
   实验室使用甲醛来保存样本。
2. 2. Formaldehyde is a toxic gas that can cause respiratory problems.
   甲醛是一种有毒气体，可能导致呼吸问题。
3. 3. Methanol and formaldehyde are both flammable liquids.
   甲醇和甲醛都是易燃液体。