_____ we have built “the Green Wall’, _____we still need to work hard to protect our environment.
I borrow a book from my friend and I can ________ it for a week.
---- ________ class are you having? ---- Math.
I don’t like physics ______ it’s too difficult for me.
---- It’s time _____ lunch. ---- OK. Let’s _____.
There _____ a ticket, a lamp and some keys on the table.