DNA受热变性时A.A280nm增高 B.磷酸二酯键断裂 C.A260nm增高 D. 发布时间:2017-06-07 00:20 │ 来源:www.tikuol.com 题型:单项选择题 问题: DNA受热变性时A.A280nm增高B.磷酸二酯键断裂C.A260nm增高D.DNA分子量变小E.G-C含量少,Tm值大
题型:单项选择题 用括号内所给词的适当形式填空。1. I __________ never __________ ( see) such a wonderful film before. 2. How much money do we need to the job __________ ( proper) 3. I happened ___________ ( meet) my old friends in the street yesterday. 4. — ___________ he __________ ( be ) to Beijing before? — Yes, he has. 5. __________ (thank) to your help, I can find my dog. 查看答案
题型:单项选择题 甲乙双方订立了一份标的额100万元的设备采购合同,双方一致同意采用定金担保方式,则该合同的定金数额不得( )。A.低于20万元 B.超出20万元 C.低于2万元 D.超出10万元 查看答案