2. A.

3、B

4、∠2 ∠5 ∠3 ∠4

5.∠ 1 and ∠2 are ipsilateral internal angles.

∠ 1 and∠ 7 are isomorphic angles,

∠ 1 and∠ ∠BAD are ipsilateral internal angles,

∠ 2 and∠ 6 are internal angles,

∠ 5 and∠ 8 are diagonal,

∠ 3 and∠ 5 are internal angles,

∠ 4 and∠ 7 are internal angles,

∠4 and 28 have no special positional relationship.

[Homework after class] 6. A

7、C

8.( 1) CD AB AE inner angle

(2) AE, AB, CD, ipsilateral internal angle

(3) AB AE CD isoseismic line

(4) internal dislocation angle of AE CD AB

9.( 1) It can be seen from the figure that the congruence angle of ∠ 1 is ∠4, because ∠2 and ∠4 are mutually adjacent complementary angles, so ∠ 2+∠ 4 =1880. Because∠

(2) It can be seen from the figure that the inner angle of ∠4 is ∠5, because ∠5 and ∠ 1 are antipodal angles, so ∠5=∠ 1,

Because ∠ 1 = 40, ∠ 5 = 40.

(3) As can be seen from the figure, the inside angle of the same side of ∠3 is ∠4, so it can be seen from (1) that ∠ 4 = 75.

There are two internal angles 10 and ∠A,

There are two isosceles angles ∠ACD and ∠ACE ∠B respectively.

There are two internal angles on the same side, which are ∠DCE and ∠ Ace ∠ACB.

They are ∠A and ∠ B.

1 1, (1) Isomorphism angles: ∠2 and ∠5, ∠4 and ∠7, ∠ 1 and ∠8, ∠6 and.

Internal misalignment angles: ∠ 4 and ∠ 5, ∠ 3 and ∠ 8.

Ipsilateral internal angles: ∠3 and ∠5, ∠4 and ∠8.

(2) ∠A and ∠8 are isosceles angles cut by straight line AB and DE by straight line AC.

∠A and∠ 5 are the inner angles on the same side formed by AC wire cutting of AB line and de line.

∠A and∠ 6 are the inscribed angles of straight lines AB and DE poked by straight lines AC.