Though it was late, _____ he went on with his work. [ ]
A. but
B. and
C. so
D. \
答案:D
()是研究产业经济学的最终目标。
光驱的倍速越大( )。
A.数据传输越快
B.纠错能力越强
C.所能读取光盘的容量越大
D.播放VCD效果越好