Explanation: on Valentine's Day (ET) the Sun unleased one of its most powerful explosions, an X-class flare.

解释：就在情人节这天(美国东部时间)，太阳释放了它最具力量的爆炸之一——一个X级的耀斑。

youdao

Explanation: on Valentine's Day (ET) the Sun unleased one of its most powerful explosions, an X-class flare.

解释：就在情人节这天(美国东部时间)，太阳释放了它最具力量的爆炸之一——一个X级的耀斑。

youdao