美股中概股盘前涨跌互现，携程跌7%

Group 1 - The core viewpoint of the article indicates mixed performance among Chinese concept stocks in the US pre-market trading, with Alibaba showing a notable increase of 3% [1] - NIO experienced a slight increase of 0.8%, reflecting a positive sentiment towards the company [1] - Baidu and Pinduoduo saw minor declines of 0.1% and 0.8% respectively, indicating some market hesitation [1] - Ctrip faced a significant drop of 7%, suggesting potential concerns or negative sentiment surrounding the company [1]