It is natural that a tree would grow best in a climate with
plenty of sunlight and rainfall. It is also expected that little sunlight or
rainfall would (11) the growth of a tree. The change from a
favorable to an unfavorable (12) can be determined by reading
the pattern of rings in a tree trunk (树干). To find out the weather of ten years
ago, (13) the rings of a tree trunk from the outside to the
inside. If the tenth ring is far from the other rings, then it is (14)
that plenty of sunny and rainy weather occurred. If the rings are
(15) together, then the climate was bad for the tree.