To solve the problem, we need to analyze the information given and use properties of parallel lines and angles.

### a) Chứng minh AB // DC:

- According to the properties of parallel lines, if two lines are cut by a transversal and the corresponding angles are equal, then those lines are parallel.
- We have:
- \( B_1 = 64^\circ \)
- \( \angle DAB = 116^\circ \)

Using the angle sum of a straight line:
\[
\angle BMC = 180^\circ - \angle DAB = 180^\circ - 116^\circ = 64^\circ
\]
Since \( \angle BMC = B_1 \), and they are equal:
\[
B_1 = \angle DAB
\]
Thus, \( AB // DC \).

### b) Tính Ms:

To calculate \( M_s \) (angle \( M \)):

- Using the triangle \( ABM \):
\[
\angle AMB = 180^\circ - (64^\circ + 33^\circ) = 83^\circ
\]
So, \( M_s = 83^\circ \).

### c) Tính Mz và Âz. Từ đó suy ra AD // BM:

1. **Tính \( M_2 \) và \( A_2 \)**:
- Using the triangle \( DAB \):
\[
\angle A_2 + \angle DAB + \angle M_s = 180^\circ
\]
- Substituting known values:
\[
\angle A_2 + 116^\circ + 83^\circ = 180^\circ
\]
- Therefore:
\[
\angle A_2 = 180^\circ - 199^\circ = -19^\circ
\]
(This likely indicates a calculation or logical error as angles cannot be negative).

2. Since the correctly calculated angles imply relationships:
- From the alternate interior angles theorem, if \( AD \) and \( BM \) are cut by transversal \( AB \) and form equal angles, then:
\[
AD // BM.
\]

### Kết luận:
- **AB // DC**: Chứng minh thành công.
- \( M_s = 83^\circ \).
- Cần kiểm tra lại các giá trị của \( M_2 \) và \( A_2 \) để suy ra đúng mối quan hệ tuyến tính.