题干

电流的热效应在科研、生产、生活中被广泛应用,但有时它也会给我们带来危害,下列情况中不属于防止电热危害的是(  )

A:电视机的后盖有许多孔

B:电动机外壳有许多散热片

C:家电长时间停用,隔一段时间应通电一次

D:电脑机箱内有小风扇

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C

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    Whether you're up for a Crocodile Dundee's adventure or you'd just like a taste of the Australian sun, the beaches in and around Sydney can offer you all that and more.

Sydney Beach

    Sydney Beach is located at Sydney's northernmost tip on an extension(延伸) of land ending at Palm Beach. Before checking out the golden sand, take a quick tour of the houses of millionaires from the art and film industries.

Palm Beach

    Only about an hour from downtown Sydney, Palm Beach offers a long stretch(延伸) of clean sand and water. With parking near the center of the beach, that leaves the rest of it as a peaceful location with a sparse population, from which you can go surfing but take care — without the huge crowds of other Sydney's beaches, Palm Beach doesn't afford quite the safety level to be found elsewhere. Volunteer lifesavers are on duty only on weekends and holidays.

Bondi Beach

    For the famous beach, Bondi Beach has to be your choice. Parking is difficult to find even on slow days, so consider taking public transport to this world—known beach in the eastern Sydney suburbs. Easily reachable by taxi, bus, and rail, Bondi Beach offers sun bathing, swimming, snorkeling, and all sorts of water sports fun. If you're in the mood for a bit of exercise, two scenic coastal walks will afford you great views and sights along the shore. Take in views from Mackenzie's Point. It starts at Bondi and heads south to Bronte Beach. But don't try to swim in Mackenzie's Bay — it holds dangers such as hidden rocks.

Bronte Beach

    Your second choice for a scenic coastal walk covers a few miles and takes you from Bronte Beach to Waverly Cemetery, where many famous Australians are buried, including the poet Henry Lawson.