如图所示的机械中，同属于一类杠杆的是（   ）

    What do Richard Branson, Jack Dorsey, and Michelle Obama all have in common? Besides being ____(extreme) successful, each of them is known for____(wake) up very early. The three famous persons' examples tell us how this habit can make a____(different) in life,____can help you ,too.

    Early rising is helpful in more than one way. To begin with, it helps us to have good health. The air is never____fresh as early in the morning. Early rising gives you time to take exercise. Besides, early rising helps us in our studies. In the morning we learn more quickly and find____Easy to learn something by heart. At last, early rising makes people able____(plan) the work for the day. We can't work well____a good plan. Just as a year's plan starts with spring, the plan for the day ought to____(make) in the morning. Therefore, if you want to____(success),it's a good idea to jump out of bed earlier.

我国国民经济的主导产业是（     ）