Mark the letter A, B, C or D on your answer sheet to indicate the correct answer that best completes each unfinished sentence, substitutes the underlined part, or has a close meaning to the original one
Trả lời câu hỏi dưới đây:
I studied English for four years in high school. ……………had trouble talking with people when I was traveling in the US.
A. bởi vậy
B. nếu không
C. mặc dù
D. tuy nhiên