Parents are used to being worried whenever their children have to travel somewhere because of there is often so much traffic.Đoạn văn40/50Mark the letter A, B, C, or D on your answer sheet to indicate the underlined part that needs correcting. Parents are used to being worried whenever their children have to travel somewhere because of there is often so much traffic. are used to being have to because of so muchGiải thíchC. because of