磁带作为贮存媒介的主要优点是：（）
A.允许直接（自由）存取；
B.使用可变长度记录（纪录长短可变）；
C.低成本；
D.不需花很大人力。
参考答案：C
问答配对（10分）
小题1:How old is John? A Yes, please.
小题2:Where is the school? B Yes, I am.
小题3:What is the last day of the week? C He is from America.
小题4:What does your father do? D He is a policeman.
小题5:What do you want to be? E It’s on Park street .
小题6:Is your mother a teacher? F Saturday.
小题7:How’s it going? G Not bad.
小题8:Where is Mr. brown from? H Yes, she is.
小题9:Can I help you? I A doctor.
小题10:Are you late for school today? J He is ten years old.
随机引物法和切口平移法是如何对探针进行标记的
