阅读理解

    I travel a lot, and I find out different “styles” of directions every time I ask “How can I get to the post office?”

    Foreign tourists are often confused in Japan because most streets there don't have names; in Japan, people use landmarks（地标）in their directions instead of street names. For example, the Japanese will say to travelers, “Go straight down to the corner. Turn left at the big hotel and go past a fruit market. The post office is across from the bus stop.”

    In the countryside of the American Midwest, there are not usually many landmarks. There are no mountains, so the land is very flat; in many places there are no towns or buildings within miles. Instead of landmarks, people will tell you directions and distances. In Kansas or Iowa, for example, people will say, “Go north two miles. Turn east, and then go another mile.”

    People in Los Angeles, California, have no idea of distance on the map; they measure distance in time, not miles. “How far away is the post office?” you ask. “Oh,” they answer, “it's about five minutes from here.” You say, “Yes, but how many miles away is it?” They don't know.

    It's true that a person doesn't know the answer to your question sometimes. What happens in such a situation? A New Yorker might say, “Sorry, I have no idea.” But in Yucatan, Mexico, no one answers “I don't know.” People in Yucatan believe that “I don't know” is impolite. They usually give an answer, often a wrong one. A tourist can get very, very lost in Yucatan!

2017年3月15日，十二届全国人民代表大会第五次会议通过了《中华人民共和国            总则》。（   ）

如图所示，长方体发电导管的前后两个侧面是绝缘体，上下两个侧面是电阻可忽略的导体电极，两极间距为d，极板面积为S，这两个电极与可变电阻R相连。在垂直前后侧面的方向上，有一匀强磁场，磁感应强度大小为B。发电导管内有电阻率为的高温电离气体，气体以速度v向右流动，并通过专用管道导出。由于运动的电离气体，受到磁场的作用，将产生大小不变的电动势。若不计气体流动时的阻力，由以上条件可推导出可变电阻消耗的电功率。调节可变电阻的阻值，根据上面的公式或你所学过的物理知识，可求得可变电阻R消耗电功率的最大值为

1912年2月孙中山认为：“帝制从此不存留于中国之内，民国的目的亦已达到。”导致孙中山得出这一结论的直接依据是（   ）

       American black bears appear in a variety of colors despite(尽管) their name. In the eastern part, most of these bears have shiny black fur, but in the west they grow brown, red, or even yellow coats. To the north, the black bear is actually gray or white in color. Even in the same litter(胎), both brown and black furred bears may be born.
       Black bears are the smallest of all American bears, ranging in length from five to six feet, weighing from three hundred to five hundred pounds. Their eyes and ears are small and their eyesight and hearing are not as good as their sense of smell. Like all bears, the black bear is timid and rarely dangerous, but if attacked, most can climb trees or cover ground at great speed. When angry or frightened, they are formidable(可怕的) enemies.
       Black bears feed on leaves, roots, fruit, insects, fish, and even larger animals. One of the most interesting characteristics of bears, including the black bear, is their winter sleep. Unlike squirrels and many other woodland animals, bears do not actually sleep through the winter months. Although the bear does not eat during the winter months, sustaining(维持) itself from body fat, its temperature remains almost normal, and it breathes regularly four or five times per minute.
    Most black bears live alone, except during the mating(交配) season. They prefer to live in caves. Baby black bears are born in January or February after a gestation(怀孕) period of six to nine months, and they stay with their mother until they are fully grown or about one and a half years old. Black bears can live as long as thirty years in the wild, and even longer in some nature reserves.