| C.Electronic routes waiting for correspondence while one is sleeping.
D.Electronic routes connected among millions of users, home and abroad.
（5）E-mail is starting to edge out（挤走） the fax, the telephone, overnight mail（快邮）, and of course, land mail（平邮）.It shrinks time and distance between scientific collaborators, in part because it is conveniently asynchronous （writers can type while their colleagues across time zones sleep; their message will be waiting）.（3）If it is not yet speeding discoveries, it is certainly accelerating communication.
3.What does the sentence “If it is not yet speeding discoveries, it is certainly accelerating communication.” most probably mean? （句子推理）
A.The quick speed of correspondence may have ill-effects on discoveries.
B.Although it does not speed up correspondence, it helps make discoveries.
C.It quickens mutual communication even if it does not accelerate discoveries.
D.It shrinks time for communication and accelerates discoveries.
Jeremy Bernstei, the physicist and science writer, once called E-mail the physicists umbilical cord（脐带）.（4）Lately other people, too, have been discovering its connective virtues.Physicists are using it; college students are using it.Everybody is using it, and as a sign that it has come of age（达到法定年龄）, the New Yorker has celebrated its liberating presence with a cartoon-an appreciative dog seated at a keyboard, saying happily, “On the Internet, nobody knows youre a dog.”