The sails were flapping against the mast.是什么意思？

The sails were flapping against the mast.

帆拍打着桅杆.

the

art. 指已提到的人（物），指说话人与听者已知的人（物），用于独一无二的事物前，与形容词最高级和序数词连用；

例句
He did have a real knowledge of the country...
他对该国的确知之甚多。

sails

n. 船( sail的名词复数 )，帆，航程，航行游览；v. 驾驶( sail的第三人称单数 )，起航，坐船旅行，掠；

例句
...one inventory of twelve sails for each yacht.
每艘快艇 12 张帆的储备

were

be的过去时复数和第二人称单数形式，有时代替 was,用于条件从句、动词 wish 之后等；

例句
Shops, houses, and vehicles were set ablaze.
店铺、房子和车辆全都陷于火海。

flapping

v. （使）上下左右移动( flap的现在分词 )，轻拍，焦急，焦虑，振（翅）；

例句
A pigeon emerges, wings flapping noisily, from the tower.
一只鸽子从塔里钻出来，扑扑地拍打着翅膀。

against

prep. 反对，对…不利，紧靠，以防；

例句
His hand brushed against hers; it could have been either accidental or deliberate.
就在有意无意间，他的手轻轻拂过她的手。

mast

n. 桅杆，栓柱，橡树果实；vt. 在…上装桅杆；

例句
I shall nail my colours firmly to the mast on this subject — as a feminist I find movies like this offensive.
我要非常明确地表明自己对这个主题的看法：作为一名女权主义者我认为这类电影是对女性的侮辱。