__________ we had read your letter __________ the true state of affairs.
A. It was until; that we understood B. It was not until; we understood
C. Until; did not we understood D. Not until; did we understood
To his disappointment, the opinion he tried to stick __________ wrong.
A. to prove B. to proving C. to was proved D. to proved
–Excuse me, Madame. Is this plane __________ take off soon?
–Oh, yes. In five minutes.
A. about to B. starting to C. beginning to D. to
An awful accident __________, 
however, occur the other day.
A. does B. did C. has to D. had to
Barrack Obama __________ President of the United States since 2010.
A. became a B. has become a C. has turned D. has been
The matter __________ your fate can't be taken for granted. You have to think it over seriously.
A. relates to B. related to C. relate to D. to relate to
