When first ________to Britain, tea was not so popular like today.[ ]

A. introduced      

B. being introduced        

C. introducing      

D. having introduced

Beck三联征的内容是（）

A.呼吸困难，脉搏细弱，血压下降

B.CPK-MB及LDH、LDH值明显升高

C.心电图ST段明显抬高、T波低平或倒置

D.心律失常，心力衰竭

E.静脉压升高、心搏微弱、动脉压降低