Presently we heard the sound of sliding boards, and an instant later a square had opened in the planks.

不久，我们听到木板滑动的声音， 片刻之后，木板上出现了一个正方形。

You know, so, you have your fin there and you put the strap right behind it so the board can't slide off backwards.

你知道，所以，你把尾鳍放在那里，把带子放在它后面，这样木板就不会向后滑动。

They provided the answer to the pioneers' need for a safe and sturdy home that an ordinary family could build quickly: they had dirt floors and sliding boards for windows.

他们满足了先驱者对普通家庭可以快速建造的安全坚固房屋的需求：他们有泥土地板和窗户滑动板。