Most foreigners feel uncomfortable when ____ in the street. 

Mr. Smith, who often helped passers-by repair their bikes, said that what he did was not paid but _______.

The organization was founded (建立) for the ________ of poor children .

Mr. Huang will ________ in the movement.

 Best of all, with online education, we can stick to our jobs and at the same time study and _______the latest knowledge.