There are v______ products on sale in the market.
Three thousand ______(听众) crowded the concert hall.
The young couple are always ______(争辩) with each other about money.
We should care for the young and ______(尊敬) the elderly.
The police ______(观察) a man in black entering the bank.
It costs me a lot to travel around the world, but it was really ______(值得的), for it broadened my views.