2) There are 1 or 3 intersections.
3) According to the same angle, two straight lines are parallel, so just draw ∠ 1=∠2, AB∨CD.
4) By finding the edges of two corners.
For example, it is necessary to judge which two straight lines ∠ 1 and ∠2 are cut into what angles by which straight lines.
Only look at the sides (***4 sides) of ∠ 1 and ∠2. If there are two sides on the same straight line, the straight line is marked as straight line A.
The other two sides are on different straight lines, which are marked as straight line B and straight line C..
Then we say line b, and line c is cut by line a.
Hope to adopt! !