问题 问答题

以下几个实验现象:    

甲:放在钟罩内的闹钟正在响铃,把钟罩内的空气抽去一些后,铃声明显减弱,    

乙:使正在发声的音叉接触水面溅起水花,    

丙:在吊着的大钟上固定一支细小的笔,把钟敲击后,用纸在笔尖处迅速拖动时,可以在纸上画出一条来回弯曲的细线.    

你认为,能说明声音的产生条件的实验现象是哪一个或哪几个?其他现象虽然不能说明声的产生条件,但是分别说明了什么问题?

答案

能说明声音的产生条件的是实验现象乙和丙;实验现象甲说明声音传播需要介质.

单项选择题
单项选择题

My dictionary defines subtle as "not immediately obvious; characterized by skill or ingenuity; clever; elusive; [even] insidious." Let us look at some concrete instances of this. (The very word itself is an example, as the letter" b" is silent in pronunciation.)"

Language can be straight-forward and directly to the point, but sometimes that takes the fun out of it. On occasion, at least, one appreciates subtleties—often as the mark of a quick wit. This particularly is true of jokes that generally have a double meaning. For example: Awaitress received only three pennies for a tip. Nonplussed, she told the customer that those three pennies told a lot about him. He took the bait and asked what they revealed. "The first penny," she said, "tells me you are thrifty." The patron agreed. "what does the second penny say" asked the customer. "It tells me you’re a bachelor." "Right again," he replied, "And what does the third penny tell you" "The third penny," responded the waitress, "tells me your daddy was a bachelor, too." How’s that for a subtle punishment

Subtleties also can be used on occasion for a good putdown. For instance, one can say a certain man was a big gun of industry. "Yes," is the counter, "he was fired several times." In this category was Mark Twain’ s caustic time bomb: "He was a good man—in the worst sense of the term."

In our day of political correctness (sometimes called the tyranny of the minority), police seldom talk about suspects, but only about" persons of interest." I guess law enforcement does not want another lawsuit on its hands. Then, too, with the campaign against fat and fried foods, Kentucky Fried Chicken calls itself KFC, figuring that few will think of "fried" that way.

The meaning of a word or phrase seems to change more rapidly today and unless one is "with it", a faux pas (失礼) can be committed. Such is the case with the term, "an exceptional child." Way back when, one would think that referred to an especially bright youngster, whereas today it indicates a handicapped youth. So, too, the word "primitive" virtually has been erased from our language and replaced with "earlier culture" and Indians are known as Native Americans.

The world of advertising is a master at subtleties with which it hopes to bamboozle (欺骗) the customer. For instance, when asked how much a gallon of gasoline costs, the reply might be something like $2.25. Yet, one must add a penny to that as a 9/10 follows the price, making it, in effect, $2.26. Cereal prices have skyrocketed over the years, but some companies claim to have held the line by keeping the price the same. What many do, however, is reduce the number of ounces in the package.

I leave the reader with the truism that subtlety, not brevity, is the soul of wit. Use it to win friends and influence people.

According to Paragraph 2, the waitress plays tricks on the patron by ()

A. telling him the particular meanings of the three pennies

B. informing him a pun which is intended to insult him indirectly

C. using a double-meaning joke as a punishment for that few tips

D. explaining to him the implied meaning of the three-pennies