Mark the letter A, B, C or D on your answer sheet to indicate the best answer of each following questions.
If you don’t have his number, you can’t phone him.
A. You can phone him unless you have his number.
B. You can’t phone him unless you have his number.
C. You can phone him unless you don’t have his number.
D. You can’t phone him unless you don’t have his number.
Đáp án B.