问题 选择题

在基因工程中用来修饰改造生物基因的工具是[ ]

A.限制酶和DNA连接酶

B.限制酶和水解酶

C.限制酶和运载体

D.DNA连接酶和运载体

答案

答案:A

改错题

把下面这封信中格式错误的地方指出来并改正。

      亲爱的爷爷: 

您好!再过半个多月就要放暑假了。爸爸妈妈准备带我回去看您老人家。您身体好吗?爷爷,我真想快点见到您,再和您一起去树林里采蘑菇。现在快要进入复习考试阶段了,我学习很紧张,我一定好好复习,带着好成绩回去见您。 

祝您

身体健康!    

                                                                                                                                    2008年6月20日     

                                                                                                                                              小刚

                                                                                                                                                         

                                                                                                                                                         

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