船机零件在交变应力长期作用下产生（）。

A．韧性断裂

B．脆性断裂

C．疲劳断裂

D．疲劳破坏

As the American writer, Mark Twain, once said, "Everybody talks about the weather, but nobody does anything about it." It is true that everybody talks about the weather; it’s the most common way of starting a conversation.
Many people think they can tell what the weather is going to be like. But they hardly ever agree with each other. One man may say, "Do you see how cloudy it is in the east It’s going to rain tomorrow." Another man will say, "Yes, it’s cloudy in the east. We’re going to have fine weather tomorrow."
People often look for the weather they want. When a farmer needs water, he looks for something to tell himself it’s going to rain; he won’t believe anything else. When friends have a picnic (野餐), they are so sure the weather is going to clear up very quickly when they sit eating their lunch in the rain.

Mark Twain wrote a book on the American weather.
[A] Right [B] Wrong [C] Doesn’t say

Almost everyone listens to what the weatherman says. But he doesn’t always tell us what we want, and once in a while he makes a mistake. Still, he probably comes closer to being correct than anyone else.