123题的41：
The contents of the raw data file SIZE are listed below:
--------10-------20-------30
72 95
The following SAS program is submitted:
data test;
infile 'size';
input @1 height 2. @4 weight 2;
run;
Which one of the following is the value of the variable WEIGHT in the output data set?
A. 2
B. 72
C. 95
D. . (missing numeric value)

50题的41：
A raw data file is listed below.
1---+------10---+----20---+---
01/05/1989      Frank      11
12/25/1987      June       13
01/05/1991      Sally        9
The following SAS program is submitted using the raw data file as input:
data work.family;
    infile 'file-specification';
    input @1 data_of_birth mmddyy10.
            @15 first_name $5.
            @25 age 3;
run;
proc print data=work.family noobs;
run;
Which one of the following is the result?
a. The program executes, but the age values are missing in the output.
b. The program executes, but the date values are missing in the output.
c. The program fails to execute because the age informat is coded incorrectly.
d. The program fails to execute because the date informat is coded incorrectly.

看答案，123题的第112题选A。50题的41题选A
我没看出来这两道题的区别在哪里。都是没有. , 但为什么一个的output是常数2，另一个就是missing。我也run了一下，结果确实如此，只是不明白。
请明白人帮着解答一下。谢谢