临床上通常将蛛网膜下腔出血分为（）和（）两大类。
参考答案：自发性；外伤性
A．
B．
C．
D．
The web is fantastic at many things, e-mail, e-commerce, for example. But _____ your name is Amazon Or Google, making money has proved hard.
A．if
B．although
C．unless
D．as
