小脑幕裂孔疝常见的病因是（）
A.外伤性颞叶血肿
B.脑积水
C.大脑半球肿瘤
D.脑水肿
E.高血压
参考答案：A, C
–Can I get out at noon?
--No. Our school rules state that no student ____ be allowed out at noon, unless he has a request form.
A．shall
B．will
C．must
D．can
下列化学方程式，书写正确的是（ ）
A．2CO+O2 点燃 . 2CO2
B．KMnO △ . K2MnO4+MnO2+O2↑
C．4Fe+3O2 点燃 . 2Fe2O3
D．2H2O催化剂2H2O+O2↑
