This is a very serious matter and the Chinese Academy of Sciences is trying to public awareness about it.
Last summer we visited abandoned farms ______ over a hundred years ago.
—Poor Steve! I could hardly ______ him just now!—Me neither. He has changed so much.
Tom says he ______ you and is helping you with the research at present.
I often go to the market with my friends _______ I can buy whatever I want.
His parents were angry when they learned he had borrowed the car ______ their wishes.