在第一，我是持怀疑态度的想法无效点火的推进剂。

At first, I was skeptical of the idea of ineffective ignition of the propellant.

youdao

在第一，我是持怀疑态度的想法无效点火的推进剂。

At first, I was skeptical of the idea of ineffective ignition of the propellant.

youdao