So far we have done a lot to build a low-carbon economy, but it is _______ ideal. We have to work still harder.
As we were asleep, __ of us heard the sound .
I suggest he __ leave at once.
The book __, it’s a best-seller.
. He has promised __ her to choose her own husband.
–-Let’s go picnicking. --- I’d love __ ,but I am too busy.