hard propellant的用法和樣例：
例句
- We shall try by means of a highly simplified development to expose certain advantages and disadvantages of solid propellant rocket systems.
我們想通過相當簡單的推導來試圖闡明固體推進劑火箭系統的某些優缺點。 - The pasty propellant is a new kind of chemical propellant derived from solid propellant.
膏體推進劑是由固體推進劑衍變而成的一種新型化學推進劑。
