It is pretty well understood __________controls the flow of carbon dioxide in and out the atmosphere today.
. I didn’t quite follow you. What was it ____ you just said about the subject?
Why don’t you bring ____ to his attention that you really don’t have time to do it for him?
Great changes have taken place in that village. It is no longer ____ it was 10 years ago, ____ it was so poor.
The way he did it was different ____ we were used to.
-- Is it necessary that he ____ to London but to New York? -- I think so, but the problem is ____ he has refused to.