To learn English well, we should find opportunities to hear English ______ as much as we can.

A．speak

B．spoken

C．speaking

D．to speak

外观呈肉眼红色的脑脊液，排除脑出血依据是

A．血液在各试管分布均匀，上清液为黄色

B．标本内有血凝块

C．红细胞数量多

D．脑脊液毛玻璃样

E．血液分布随采集试管号增加而减少，上清液五色透明