辙叉心宽0～50mm垂直裂纹，一条裂纹长度超过50mm，判（）。
参考答案：重伤
Only when __________________ permission _______________ allowed to enter the lab.
A．a teacher has given; are the students
B．has a teacher given; are the students.
C．has a teacher given; the students are
D．a teacher has given; the students are
