黄土高原千沟万壑的地表形态的原因是[ ]
A．流水搬运作用
B．风力沉积作用
C．流水侵蚀作用
D．流水沉积作用
答案：C
Only after they had discussed the matter for several hours _______a decision.
A they reached B did they reach C they reach D do they reach
互联网的主要技术指标包括带宽、时延、吞吐率和________。
