Cities may seem like an unlikely place for plant life to blossom. Car fumes, polluted water, and toxic metals in dirt are only a few of the obstacles to growth.

• 城市似乎不像是植物_生长的一个好地方。车排出的烟雾，被污染过的水以及埋着有毒金属只是植物生长中要克服的一小部分。