square delayed pulse

例句：

1. 1. The table isa perfect square.
   这张桌子是完美的正方形。
2. 2.The room is squared off with walls.
   房间被墙壁围成了一个正方形。
3. 3. The squareof a number is the product of itspositive and negative integer powers.
   一个数的平方是其正整数幂和负整数幂的乘积。