eraser tool的用法和樣例：
例句
- We have to erase the unnecessary parts of both wings, choosing the Eraser Tool.
多余的部分用橡皮擦工具將其擦除。 - The cursor can become an eraser tool and erase anything previously entered, or it can become an ellipse tool and draw any number of new ellipses.
光標可以變成橡皮擦，擦除先前輸入的任何內容，也可以變成橢圓工具，繪制多個(gè)新的橢圓。
