在文件系统中,文件的逻辑结构可分为两类,它们是流式文件和______。
参考答案:记录式文件
New York City had a deeper harbor than other Atlantic seaports was one reason for its prosperity during the early 19th century.
TMS的δ=0,从化合物的结构出发,它的正确含义是()。
A.不产生化学位移
B.化学位移最大
C.化学位移最小