Last Sunday, my cousin took me to the zoo. In the zoo we saw ______ elephant. ______ elephant was from

Africa.[ ]

A. the, An

B. an, An

C. an, The

董先生，70岁，因胸骨后闷痛2小时入院，心电图示急性广泛前壁心肌梗死。住院当晚，护士发现其反应迟钝，面色苍白、皮肤湿冷、脉搏细弱，应首先考虑发生了（）

A．心源性休克

B．心室颤动先兆

C．急性左心衰竭

D．并发脑栓塞

E．急性肾衰竭