用succeed的适当形式填空

1. What's the secret of your____?

2. There has been low rainfall for two____years.

3. Who is the likely____to Blair as party leader?

4. She has won the award for the third year in____.

5. They were____in winning the contract.

在我国古代，简单机械就有了许多巧妙的应用，护城河上安装的吊桥装置就是一个例子(如图所示). 在拉起吊桥过程中，吊桥相当于一个          杠杆，C处的装置是一个             滑轮，它的作用是                     。