顺风的英文：
a free wind
before the wind
down the wind
downwind
propitious winds
tailwind

参考例句：

I looked up and saw the clouds rack at an unusual rate.
我抬头看到云朵在顺风飞驰。

Twelve hundred galleys floated at Aulis, waiting for a favourable breeze to swell their flagging sails
一千二百艘船只聚集于奥利斯，等着风鼓船帆，顺风而行。

One of a pair of movable boards or plates attached to the hull of a sailing vessel to reduce downwind drift.
下风板，减横漂板装在帆船船体外侧的一对可移动的木质板或金属板的一块，用于减弱顺风漂移

Sail with the wind behind the ship
顺风航行.

The sailing ship is flying before the wind.
帆船顺风航行。

The fleet began to fill away on a northerly course.
船队开始顺风向北航行。

To change the course of(a ship)by turning the stern windward.
使顺风通过把船尾转向风改变(船)的航向

They watched the racing fleets jockey for the favoring wind
他们看着参赛船队抢占顺风的有利位置。

The wind being favourable, I steered the same course that I had done the day before.
正遇着顺风，我仍旧按照前一天的航路把舵前进。

They watched the racing fleets jockey for the favoring wind.
他们看着参赛船队抢占顺风的有利位置。

free是什么意思：
adj. 自由的；免费的；空闲的；任意的；免税的；游离的
adv. 免费地；自由地
v. 释放；免除；使自由，解放

Freedom is not free.
自由不是无偿的。

Be covered by free Medicare / be entitled to free medical care
享受公费医疗

It depends on free oxygen or air.
它依靠大量的氧或者空气。

wind是什么意思：
n. 风；吞下的气
v. 曲折而行；缠绕；使喘大气

The wind is blustering.
风在呼啸狂吹。

Wind power: Use of the energy in winds to produce power.
风力:利用风的能量来产生动力。

wind energy potential
风能潜力

before是什么意思：
prep. 在…之前；优于，先于；当面
conj. 在…之前
adv. 先前，从前

Rain before seven;fine before eleven
雨过天晴

They corned their horses before the journey.
他们在启程前用玉米喂马。

The army was arrayed before the commander.
部队在指挥官前列好阵势。