He reduced speed and turned sharp left.

他减慢速度，向左急转。

For every ship that passes through the Santa Barbara Channel at or below the reduced speed of 12knots, the company that owns the ship will be paid $2,500.

对于每艘穿过圣巴巴拉海峡，且速度达到或低于12海里每小时的船只而言，拥有该船舶的公司将支付2500美元。

Some Bridges had reduced speed limits imposed.

一些桥梁已降低了限速标准。

He reduced speed to forty kilometers an hour.

他把速度减到每小时四十公里。

Reduced speed = deterioration, or willful reduction of speed to be "safe"

速度降低，如机器老化或为了“安全”故意降低速度。