USAGE NOTE 用法说明: still and 和 yet
Use still to talk about a situation that continues to exist at the present time. still is usually used before the verb. still 用于表示现在依然存在的一种情形，一般用于动词之前:
I still see Jeannie from time to time. 我偶尔还会和珍妮见面。
The club still sends him the newsletter. 那家俱乐部仍然给他寄简讯。
However, you should use still after the verb 'to be'. 然而，still 应该用在动词 to be 之后:
He was still waiting three hours later. 三小时之后他还在等着。
Jo's still upset. 乔还在生气。
She's still on the phone. 她还在打电话。
Use yet in negative sentences and questions to talk about something that you expect to happen, but which has not happened. Yet is usually used at the end of a sentence. yet 用于否定句和疑问句中，表示某事预期会发生却尚未发生。yet 一般用于句末:
I haven't finished the book yet. 我还没看完这本书。
Is Mark back from lunch yet? 马克去吃午饭回来了吗？