1. Spaceships are very precious and great. 宇宙飞船非常珍贵、非常伟大。
2. They launched at least 2 spaceships into outer space each year. 他们每年至少向外太空发射两艘宇宙飞船。
3. There may be giant plankton on gaseous planets. They float in a thick atmosphere like small spaceships and live by "eating" lightning. 气态星球上可能存在巨型浮游生物。它们像小型飞船那样漂在厚厚的大气中，靠“吃”闪电获取能量为生。
4. There are just two hydrogen atoms per cubic centimeter on average in space, which poses no threat to spaceships traveling at low speeds. 太空中平均每立方厘米只有两个氢原子，这对低速飞行的宇宙飞船不构成威胁。
