• adj. 追溯的；有追溯效力的；反动的

retro-,向后，往回，active,有效力的。

retroactive (adj.)

1610s, from French rétroactif (16c.) "casting or relating back," from Latin retroact-, past participle stem of retroagere "drive or turn back," from retro- "back" (see retro-) + agere "to drive, set in motion" (see act (v.)). Related: Retroactively.

1. The seagulls swirled in aerial combat over the barges.

海鸥盘旋在驳船上方，展开空中的搏斗。

来自柯林斯例句

2. a flock of seagulls

一群海鸥

来自《权威词典》

3. Seagulls followed in the wake of the huge ship.

海鸥尾随于大船之后.

来自《简明英汉词典》

4. The seagulls were wheeling in the air above the ship.

海鸥正在船上面盘旋.

来自《现代汉英综合大词典》

5. There is a seagull perched atop the mast.

有一只海鸥停歇在桅杆上.

来自《简明英汉词典》