Giúp em làm câu (3) và giải thích thôi ạ The relationship between students and teachers is less formal in (1) __________USA than in many other countries. American students do not stand up when their teacher enters the room. Students are generally encouraged to ask questions during class, to stop in the teacher’s office for extra help, and to phone if they are absent. Most teachers let students enter class late or (2) ________ early if necessary. (3) __________, students are still expected to be (4) _________ to their teachers and fellow classmates. When students want to ask questions, they usually raise a hand and wait to be called on. When a test is being given, talking to a classmate is not only rude but also risky. Most American teachers consider that students (5) ________ are talking to each other during a test are cheating. 3. A. Moreover​ B. However. ​C. Therefore​ D. Meanwhile