急性心肌梗死时，恢复早且特异性较高的酶是( )
A．乳酸脱氢酶
B．乳酸脱氢酶同功酶LDH
C．谷丙转氨酶
D．谷草转氨酶
E．肌酸磷酸激酶
参考答案：E
动点P在x轴与直线l：y=3之间的区域（含边界）上运动，且到点F（0，1）和直线l的距离之和为4．
求点P的轨迹C的方程．
______ studies how sentences in spoken and written language form larger meaningful units such as paragraphs, conversations, and interviews.
A．Communicative Language Teaching
B．Meaning negotiation
C．Discourse analysis
D．Pragmatics
