The Internet is a (66) network of networks which interconnects (67) ranging from the simplest personal computers to the most sophisticated mainframes and supercomputers. This network of networks is used for an extraordinary range of purposes - long distance collaborations, retrieving free software and documents, (68) library catalogs, (69) in t6 supercomputers - the list of current Internet activities and (70) is large and the range of possible future applications is as unlimited as our imagination.

A．logging

B．going

C．coming

D．achieving

中央性前置胎盘大出血的治疗方法，下列哪项是正确的

A．催产素引产

B．剖宫产

C．胎头吸引助产

D．如为臀位，行足牵引

E．人工破膜，头皮钳牵引压迫止血