下列药物对肝脏氧供和氧耗平衡影响最明显的是()
A．恩氟烷
B．异氟烷
C．氟烷
D．地氟烷
E．七氟烷
参考答案：C
下列生产方法中属于压力加工的有（）。
A.自由锻造
B.模锻
C.冲压
D.特种加工
E.回火
—English has a large vocabulary, hasn't it?
—Yes. ______ more words and expressions, and you will find it easier to read and communicate.[ ]
A. Know
B. Knowing
C. To know
D. Known
