作物脱毒、改善畜产品的品质、抗除草剂作物、可保存的干扰素、检测有毒物质依次是下列哪项生物技术的应用   
①基因工程   ②细胞工程   ③蛋白质工程   

如图所示，下列工具的使用，属于费力杠杆的是(    )
        

已知四边形ABCD为平行四边形，要使得四边形ABCD为矩形，则可以添加一个条件为____．

 从下面方框中选择适当的词填入短文中，使短文通顺正确（注意有些词要用适当的形式）。

    One day, Mr. White told the class to get ready for a hobby show. The students ____  the whole morning getting what they were going to show.
     All the students came back on time but Bob, the laziest ____ in his classmates' eyes. It seemed that it was very ____  for Bob to have a hobby. But to their surprise, Bob came back with many ____ stamps in his hand. Mr. White was very happy after watching them. However, Bob was going to ____ them back.
“Bob, you can't take them back until the others watch them this afternoon,” said Mr. White.
“But I am sorry they are my brother’'s,” he answered. “He doesn't want them to be out of our home for long. He's afraid that they will be ____  .”
“Bob, you should show some of your own ____  here, not someone else's. Mr. White became kind of angry.
But Bob's words made him even ____ . “Mr. White, it's true that I have a hobby. My hobby is watching my brother collecting stamps.”