When you see some waste paper on the ground, you should _______ and put it in the trash bin.

No one was sure exactly__________ he wanted

Can you tell me _____ the birdwatchers in Zhalong Nature Reserve? I only know that _____ of them are from our school.

What do you think about Chinese Post-90s generation ?–They are ­­­­­­­­­­­­_________ from those born before them. They are very aggressive and pretty confident because they never felt hardship.

You don’t know ______ I want to see you again. It’s a year since I last saw you.[ ]