You can visit the Bird's Nest and the Water Cube and visit Qianmen Street (just opened, many Beijingers haven't come yet). If you are interested in IT products, you can also visit Zhongguancun. If you like basketball, I recommend you to watch a basketball game at the Capital University Gymnasium, which is always available at night and free of charge.
Beijing-Tianjin intercity is at Beijing South Railway Station and Beijing Railway Station, depending on which station you bought. There are usually many south stations.
1, when you arrive in the morning, you can take the No.8 express to the space bridge of South Station Square, and take the No.86 bus directly to the Bird's Nest.
2. Take the subway from the Bird's Nest to Huang Zhuang, Haidian in the afternoon, get off and walk north to Zhongguancun.
3. Go to the Capital University Gymnasium to watch the football match in the evening. Take bus No.302 from Zhongguancun to the west of Jimen Bridge, just across the road.
4. I went to Qianmen the next day. I didn't know which hotel, so I took the subway and could go shopping for half a day. Then walk along Tiananmen Square-Tiananmen Square-East Chang 'an Street-Wangfujing from the front door and play along the way. I went to Wangfujing Street to have a look. There is a snack street where you can eat snacks, but it should be noted that the snacks in Beijing are not as delicious as those in Tianjin. It's very miscellaneous, not distinctive, there may be eighteen street twists, and dogs ignore it. Pay whatever you like.