这三个词可以作为同义词使用。almost 属于最普通用词，practically 多用于口语，而 virtually 则相对较正式。如：

1. To save money now is practically impossible. 现在要存钱几乎不可能。

2. With so muchloud music, conversation was almost impossible. 音乐声那么大，几乎没法交谈。

3. It is difficultto find work these days, but for blind people it is virtually impossible. 现在找工作很难，而对盲人来说则几乎不可能。