颅脑外伤后，下面哪种情况可引起低颅压综合征（）
A.颅内积气
B.脑脊液漏
C.颅底骨折
D.颅骨粉碎性骨折
E.颅内血肿
参考答案：B
若分式方程x/x-4=2+a/x-4有增根，则a的值为（ ）
There is going to ______ a basketball match in the playground this afternoon. [ ]
A. have
B. has
C. is
D. be
