16.【单选题】“人的思维是否具有真理性，这并不是一个理论的问题，而是一个实践的问题。人应该在实践中证明自己思维的真理性，即自己思维的现实性和力量，亦即自己思维的此岸性。”这一论断说明了：（）

It took me a while to ____ this word in this thick book.

____ passengers do not have to go through customs.

It took him a full day to ____ those bags.

The captain needs to be ____ of this.

I am terribly sorry I can＇t ____ your invitation due to my business.

The e-ticket is very ____ for everyone.

You can check the ____ of Spring Airlines for the flight to Guangzhou.

There are verious ____ of movies on the plane.

Can you tell the ____ between the boarding pass and the ticket?

Which one should be taken out of packed baggage to scan at the security check point?