sas 新手 刚学到macro 编程

这是老师给的一道题：
Write a SAS program that uses four user-defined macro variables and three automatic macro variables to specify the following in a PROC PRINT step:
a. The most recently created data set as the data set to be printed.
b. The first observation to be printed via a FIRSTOBS= option.
c. The last observation to be printed via a OBS= option.
d. A first title line that displays:
          i. The name of the most recently created data set (i.e., the data set being printed).  
          ii. The range of observations printed.
e. A second title line that displays:
           i. The day of week associated with the beginning of the current SAS session.
           ii. The time of day associated with the beginning of the current SAS session.
f. Whether or not to included observation numbers in the PROC PRINT output.
g. Whether or not to include any assigned variable labels from the data set in the PROC PRINT output.


For this exercise, turn in:
• Your SAS program containing the PROC PRINT step with macro variable references.
• The %LET statements that would precede your program in part a in order to print out observations 10 through 20 using any assigned variable labels and with observations numbers.
• The %LET statements that would precede your program in part a in order to print out observations  5 through 10 using variable names as labels and with no observations numbers.

请教一下，什么叫可或者不可显示 obs 和label啊 还有这一个程序根本不可能啊  还是我题目看错了 反正研究了 一下午 还是没搞明白。

谢谢大家帮忙了