main sequence的用法和樣例：
例句
- In comparison to their size on the main sequence, the stars now become giants.
同它在主星序上的大小相比，恒星現在就成了巨星。 - When a massive proto -star approaches the main sequence, its surface temperature is low and it can not ionize the ambient gas.
當一個(gè)大質(zhì)量原星接近主星序時(shí)，它的表面溫度是低的，因而不能電離周?chē)臍怏w。
