误：I don't still understand what you mean.
正：I still don't understand what you mean.
析：still 用于否定句时，应放在 don't, haven't, didn't 等否定词之前。又如：
He still doesn't understand. 他仍然不懂。
The breakfast I ordered still hasn't arrived. 我要的早餐还没有来。
I still haven't heard from her. 我还是没有听到她的消息。
When I came back at midnight she still hadn't finished. 我半夜回来时，他还没有做完。
I've been waiting for an hour and he still hasn't turned up. 我等了一小时了，可他还没来。
I still haven't thanked Aunt Lucy for her present. 对露茜姑姑送的礼物我还没有表示感谢呢。
I've been married to you for sixteen years and I still don't understand you. 我和你结婚16年了，可我对你仍然不了解。
注：有时 still 也可放在助动词与否定词(not)之间，但较少见，如：
A solution still hasn't been found. / A solution has still not been found. 还没有找到解决的办法)，
但是不能说：A solution hasn't still been found.