题干

市面上出售一种装有太阳能电扇的帽子(如图所示).在阳光的照射下,小电扇快速转动,能给炎热的夏季带来一丝凉意.该装置的能量转化情况是(  )

A:太阳能→电能→机械能

B:太阳能→机械能→电能

C:电能→太阳能→机械能

D:机械能→太阳能→电能

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A

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    Denali National Park, Alaska

    History

    Within Denali National Park, the Toklat River will always have a special significance, as it was the location where naturalist Charles Sheldon built a cabin and was so moved that he fought to preserve the land. He moved back east and spent nine years lobbying (游说)to create Alaska's first national park.

    When to Visit

    To avoid the crowds, visit in June, but keep in mind that there are up to 21 hours of sunlight in Alaska in summer. If it seems like a bit much for your taste, try visiting in late August or September.

    If you visit to climb Mount McKinley, May and early June are the best times to climb.

    Major Attractions

    It is difficult not to see Denali's largest attraction towering 20,320 feet high. Mount McKinley can even be seen up to 70 miles away on a clear day. If you brave the climb to the top, you will be rewarded with charming views of the Alaska Range.

    Sable Pass is a prime spot to view grizzly bears. Closed to off-road foot traffic, the area is popular for bears feeding on berries, roots, and even occasionally on other mammals.

    Beginning at just below the summit of Mount McKinley, Muldrow Glacier flows 35 miles through a gorge and across the tundra. Twice in the last hundred years, the Muldrow has surged (涌动), most recently in the winter of 1956-1957.

Accommodation

    Five campgrounds are located within the park, and many are open from late spring to early fall.Note: reservations are strongly recommended during summer. Riley Creek campground is open all year round, and all but two (Sanctuary and Wonder Lake) offer RV (可供居住的大篷车)sites.

    Also within the park are a few lodges (旅馆)—North Face Lodge, Denali Backcountry Lodge and Kentishna Roadhouse.