Achieving a high degree of proficiency in English as a foreign language is not a mysterious _____ without scientific basis.
It is one of the funniest things ______ on the Internet so far this year.
You ______ be hungry already — you had lunch only two hours ago!
______that he was in great danger, Eric walked deeper into the forest.
—Shall we go out for dinner tonight? —______.
Why are you so anxious? It isn’t your problem ______.