1 At first glance, a forest appears to be a haphazard collection of trees, shrubs, vines, and flowers.
2 Leaves are not distributed accidentally on a plant stem, but are arranged in a very precise way that assures them the maximum light.
3 Medieval cities grew rapidly when they had harbors nearby.
4 Because of harsh weather conditions, more than a dozen states in the United States were declared disaster areas in 1977.
5 The best olive oil is obtained from olives that are harvested just after they ripen and before they turn black.
答案：1A 2C 3D 4A 5C