label to each of the trees, with detailed introduction of their features, and visitors will know more about them and how to protect them.
A. To attach
B. Attach
C. Attached
D. Having attached
网友回答
A. To attach
(答案→)B. Attach
C. Attached
D. Having attached
解析：考查短语：attach … to 把……贴在，把…附加在，此题还考查句型：祈使句+and 后用一般将来时态。所以选B。