单项选择题
A. seem to be of no use B. can help people get a better comprehension of the language C. are easy to master D. have gone beyond our mother’s reach
A. he murdered one of his classmates with a knife B. he was not interested in studies and killed his parents C. he stole something from his fellow pupils D. he stabbed his teacher through heart with a knife
A. Vitamin A B. Vitamin B C. Vitamin C D. Vitamin D