当黑龙江还是冰天雪地时，海南岛已是春耕大忙了，这是由于我国的（    ）

根据短文内容。选择适当的短语完成句子。    A man goes to a fast food restaurant for lunch. "Hi!" a waiter says. "Can I help you?"
    "I'd like a hamburger。French flies and a medium pizza, "says the man.
    "Anything else?'' the waiter asks.
    "No, "the man answers. "That's all. ''
    "Is that for here or taking away?" the waiter asks.
    "Taking away, "says the man.
    The man pays for his lunch. The waiter puts the man's lunch in a bag. 'The man takes the bag away.
    "Thank you!" the waiter says. "Have a nice day."
    The man walks to a park. He sits down and opens the bag. To his surprise(使他吃惊的是), there are no hamburgers in the bag. There are no French fries. There is no pizza. There is money(钱)in the bag a lot of money. The man counts the money--2, 000 dollars!
    Why is the money in the bag? The man doesn't know. Do you know? Can you guess?

A. to a park      B. a lot of money      C. the man's lunch in a bag D. "I'd like a hamburger, French fries and a medium pizza.'' E. to a fast food restaurant for lunch

已知y关于x的二次函数 $y=a{x}^2\text{-}bx+2$ （ $a\ne 0$ ）．

按要求解决下列问题：

下列各图分别描述了生活中发生的一些事例，其中符合安全用电原则的是（   ）