Obligative
专性的
🗣️ 情景例句
That's another surprise.
这是另一个惊喜。
When it started raining, I was playing outside.
当雨开始下的时候，我在外面玩。
it requires 97 per cent less energy to travel the quarter of a million miles from the Moon to Earth-orbit than the 200 mile-journey from Earth's surface into orbit!
因此，从月球到地球的25万英里所消耗的能量要比从地球表面进入地球轨道的200英里所耗能量少97%。