1
2
3
6
7
10
15
16
18
19
20
22
A
B
30
32
35
Beginning
40
43
48
50
51
56
57
59a
59b
text
62
68
69
exercises
end
72
73
74
75
76
77
80
82
83
S14-15
S16-18
S19
Questions
86
87a
87b
89a
89b
94
s12-14
s15-18
s19-end
98
99
99s14
19-end
101
102
106
107
110
111
112
113a
113b
114
115
116