this table cannot be shown because it is not in import mode.

Hi yanzhao_LBS 

The datasource will dicatate wether you can connect to the data model as a direct query or load.

If direct query you cannot look inside the tables. 

There is a way of jerry rigging it by using Create Table and then setting the new table equal to the old table. This will force the table to load and is known as a calculated table. You MUST remove calculated tables before pubishing as models connected to Semantic Direct Queries DO NOT support calculated tables.

https://learn.microsoft.com/en-us/power-bi/connect-data/service-datasets-understand

Here is an article explaining import modes:

https://learn.microsoft.com/en-us/power-bi/connect-data/service-dataset-modes-understand