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1·These biros can all write upside down.

这些原子笔可以从各个方向书写。

2·Removing ink stains caused by biros, fountain pens and artist's ink from clothing is not an easy task but it is doable.

要除去圆珠笔、钢笔、美术作品墨水留下的污渍，可不是那么容易的事，却也可行。