After several days of social activities, I decided to       _ on my research on the human behaviors. 

Look at the timetable. Hurry up!! Flight 4026 _____ off at 18:20.

They didn’t ________ the true meaning of what the boss had said, and thus their task almost completely failed. 

The president spoke at the business meeting for nearly an hour without ______ his notes.

Peru is, ______, a very beautiful country、It is so attractive that tourists from all over the world come to visit it.