You can only judge how high something is when you know how far away it is

　　知道了某物的距離才能判斷其高度。

　　We can find the size of something by means of measurement.

　　我們可以用測(cè)量法求得某物的體積。

　　It's important to try and make something of your life.

　　在一生中有所成就是很重要的。

　　First try to do something that is within your scope.

　　你先試著做一件自己力所能及的事。

　　I'm sure she's keeping something back from us.

　　我肯定她有什么事瞞著我們。