On an island there are exactly seven towns: T, U, V, W, X, Y and Z. All existing and planned roads on the island are two-way and run perfectly straight between one town and the next. All distances(距离；路程) by road are distances the main square of one town to the main square of another town. U is the same distance by road from T, V and W as Y is from X and Z. The following are of the now existing roads on the islands.
Road 1 goes from T to V via (经由) U.
Road 2 goes directly from U to W.
The triangle (三角形) road goes from X to Y, from Y on to Z, and from Z back to X. Any main square reached by two roads is an interchange (立交桥) between them, and there are no other interchanges between roads.
68. Which of the following sketches is correct?
A. W B. U
T U V W V T
C. T U V W D. T W V
U
69. Draw a sketch of the Triangle Road. Which of the following sketches is correct?
A. Z B. Y X
Y
Z
X
C. X Z D. Y Z
Y X
70. Which of the following is a town from exactly two other towns can be reached by road?
A. T B. X C. V D. W
