The flowers sweet in the botanic garden attract the visitors to the beauty of nature.A. s

问题补充：

The flowers sweet in the botanic garden attract the visitors to the beauty of nature.

A. smelling

B. smelt

C. to smell

D. to be smelt

答案：

(答案→)A. smelling

B. smelt

C. to smell

D. to be smelt

解析：句意：植物园里的这些花闻起来非常甜吸引了参观者来欣赏大自然的美。这里整个句子有动词attract，所以空格处需用非谓语动词，这里smell是系动词没有被动，故选A。