So far we have done a lot to build a low—carbon economy, but it is ____ideal. We have to work still harder.

Mistakes don’t just happen; they occur for a reason. Find out the reason, and then making the mistake becomes ______.

Sometimes he was made in an embarrassing situation because he was always too_________ in his work.

The listeners were much        than hoped. There were so many tickets left.

The pilot asked all the passengers on board to remain ______ as the plane was making a landing.