下列是美国资本主义发展过程中的两大障碍的是
①英国殖民统治②美国联邦政府③黑人奴隶制度④印第安人的反抗[ ]
A.②③
B.③④
C.①③
D.①②
答案:C
This English newspaper is very easy for the students; there are _____ new words in it. [ ]
A. little
B. a little
C. few
D. a few
哪种广域网技术是在 X.25 公用分组交换网的基础上发展起来的?
A.ATM
B.帧中继
C.ADSL
D.光纤分布式数据接口