由1﹣丙醇制取，最简便的流程需要下列反应的顺序应是（　　）

a．氧化　b．还原　c．取代　d．加成　e．消去　f．中和 g．加聚　h．酯化．

竖直平面内有两个半径不同的半圆形光滑轨道，如图所示，A、M、B三点位于同一水平面上，C、D分别为两轨道的最低点，将两个相同的小球分别从A、B处静止释放，当它们各自通过C、D时，则（   ）

    I have a good friend from Australia. Her name is Laura. Here is a photo of her family.

    There is a nice girl and a1boy in the photo. The boy is her brother David. Laura is thirteen2, David is ten.3 do they look like? Laura is not fat and she is not thin4. She is of medium build. She has a round5like an apple. Her mouth is small, but her eyes are big. Her hair is6and blonde. Laura likes purple and she is often in purple clothes. She7being a singer. What about David? He is a little thin. David doesn't like8. His favorite color is green. David wants to be an actor. They like9movies very much. They often go to the cinema when they are free. It's relaxing for10to see a movie. You can also see a black dog in the photo. It's their pet dog Cici.

他是我的爸爸。