1. If you hold China passport (even if you also have Canadian PR Card), you can not transfer through US airports if you do not have US visa .
2. If you hold China passport, you cannot fly to Hong Kong as your destination if you do not have HK visa. For example, you cannot buy China Eastern Airline from Vancouver to Shanghai to HK. However, you can fly from Vancouver to HK (directly flight)., but only 7 days stopover in HK, then you need to go to other country.
3. If you hold China passport, you can stopover in Tokyo 3 days (72 hours) , then go to other country.
4. If you hold China passport, you can stopvoer in Seoul 7 days , then go to other country.
5. If you hold China passport, you cannot stopover in Taipei without Taiwan's permit. You can just transfer ASAP.
Information from Lao Zhang 's FlyGreatChina
Above information is only for refeernce. Please double check with embassy of that country.