Netizens are frequently reminded to be ________ about revealing (透露) their personal information on the Internet.

To our anger, many poverty-stricken counties build luxurious office buildings instead of _______ money to improve the miserable conditions of local schools.

Do you remember ____ he came? –Yes, I do.He came by car.

There ______ a dog and two cats in the picture.

Sam _____ some knowledge of the computer just by watching others working on it. [ ]