铸造前腭杆前缘距离余留牙牙龈缘的距离()
A.≥3mm
B.≥4mm
C.≥5mm
D.≥6mm
E.≥7mm
参考答案:D
Once fighting_____ between the two villages and many people were killed.
A.broke out
B.was broken out
C.had broken out
D.had been broken out
打乱传统的按年龄编班的做法,而按学生的能力或学习成绩编班,这是( )
A.外部分组
B.内部分组
C.设计教学法
D.道尔顿制