The text is for questions 17 to 20.

    If you go to Australia, Adelaide is worth to visit. Why? Mining and agriculture brought riches to the city, and today, Adelaide's affluent heritage is still proudly on display. Magnificent private mansions and grand public buildings command an important place amid the modern high-rises. Museums, galleries, gardens, and gourmet restaurants are some of the city's finest treasures, and lovers of the arts can indulge in opera, symphony, and a flourishing live music scene. Explore the area with our list of the top tourist attractions in Adelaide.

1. Wander through the wrought-iron gates at the east end of North Terrace and enter a wonderland of botanical treasures. Established in 1855, Adelaide Botanic Garden features educational themed plantings such as medicinal plants, a Mediterranean garden, Australian native species, and a wetland designed to sequester enough water to eventually irrigate the entire grounds.
       The Santos Museum of Economic Botany provides insight on the important role plants play in everyday life through a series of permanent collections. Other garden favorites include the palm house, the Bicentennial Conservatory with lowland rainforest plants, night-flowering Amazonica water lilies, and Australia's oldest avenue of Moreton Bay fig trees. Exploring these beautiful gardens is one of the best things to do in Adelaide for free.
2. In the heart of Adelaide's cultural precinct, the Art Gallery of South Australia exhibits one of Australia's finest art collections. The elegant, colonnaded Victorian building, established in 1881, sets the tone for the eminent works within its walls. The collection crosses all mediums, from sculpture, paintings, textiles, metalwork, and photographs to ceramics, jewelry, and furniture.
       The Australian collection spans the colonial days to the present, including indigenous and Torres Strait Islander art. European works highlight pieces from the Renaissance to the present day, and Asian exhibits include Australia's only dedicated Islamic gallery. Important Nort American pieces are also on display, as well as some evocative avant-garde sculptures.
3. The South Australian Museum, adjacent to the State Library, is a top research facility renowned for its Aboriginal heritage collections. In addition to the excellent Australian collection, you can admire artifacts from the South Pacific Islands in the permanent Pacific Cultures Gallery, gaze upon Egyptian antiquities, and learn about local flora and fauna in the South Australian Biodiversity Gallery.
       Children love the natural history exhibits with stuffed specimens, fossils, and skeletons, and special exhibits mean there's always something new to see. Best of all, this museum is one of the many things to do for free in this culture-rich city.

(Adopted from: https://www.planetware.com/tourist-attractions-/adelaide-aus-sa-a.htm (April 12, 2020))

What attraction can people see in Adelaide?