第20题: [单项选择]患儿,男,替牙(牙合)时期,牙齿排列不齐,经医生检查,以下不属于乳牙与恒牙鉴别要点的是() A. 恒牙牙冠呈乳白色偏黄、乳牙牙冠呈乳白色偏青白 B. 恒牙颈嵴突起明显,乳牙颈嵴突起不明显 C. 乳牙牙冠颈嵴突出 D. 恒前牙根尖可偏远中,乳前牙根尖可偏唇侧 E. 恒牙牙冠颈部缩窄,形态上与牙根的分界不大明显 参考答案:B 答案解析:恒牙颈嵴突起不明显,乳牙颈嵴突起明显。
第25题: [单项选择]Questions 23 to 25 are based on the passage you have just heard.What’s the chief duty of every government A. To protect persons and property. B. To collect taxes. C. To teach and train citizens. D. To save natural resources for future use. 参考答案:A 答案解析:[听力原文]23-25 We use all sorts of services without thinking how we get them. But such services