Don't walk on the grass or you'll be in trouble with the law.
不要踏进草地,不然的话法律会找你麻烦的。
One swallow does not make a summer.
一燕不成夏。
As a shipbuilder, Cockerell was trying to find a solution to the problem of the wave resistance which wastes a good deal of a surface ship's power and limits its speed.